Influence of environmental conditions on the toxicokinetics of cadmium in the marine copepod Acartia tonsa.

Science.gov (United States)

Pavlaki, Maria D; Morgado, Rui G; van Gestel, Cornelis A M; Calado, Ricardo; Soares, Amadeu M V M; Loureiro, Susana

2017-11-01

mMarine and estuarine ecosystems are highly productive areas that often act as a final sink for several pollutants, such as cadmium. Environmental conditions in these habitats can affect metal speciation, as well as its uptake and depuration by living organisms. The aim of this study was to assess cadmium uptake and depuration rates in the euryhaline calanoid copepod Acartia tonsa under different pH, salinity and temperature conditions. Cadmium speciation did not vary with changing pH or temperature, but varied with salinity. Free Cd 2+ ion activity increased with decreasing salinities resulting in increased cadmium concentrations in A. tonsa. However, uptake rate, derived using free Cd 2+ ion activity, showed no significant differences at different salinities indicating a simultaneous combined effect of Cd 2+ speciation and metabolic rates for osmoregulation. Cadmium concentration in A. tonsa and uptake rate increased with increasing pH, showing a peak at the intermediate pH of 7.5, while depuration rate fluctuated, thus suggesting that both parameters are mediated by metabolic processes (to maintain homeostasis at pH levels lower than normal) and ion competition at membrane binding sites. Cadmium concentration in A. tonsa, uptake and depuration rates increased with increasing temperature, a trend that can be attributed to an increase in metabolic energy demand at higher temperatures. The present study shows that cadmium uptake and depuration rates in the marine copepod A. tonsa is mostly affected by biological processes, mainly driven by metabolic mechanisms, and to a lesser extent by metal speciation in the exposure medium. Copyright © 2017 Elsevier Inc. All rights reserved.

Expression of hsp70 and ferritin in embryos of the copepod Acartia tonsa (Dana) during transition between subitaneous and quiescent state

DEFF Research Database (Denmark)

Nilsson, Birgitte; Jepsen, Per Meyer; Rewitz, Kim Furbo

2014-01-01

Subitaneous eggs of the neritic calanoid copepod Acartia tonsa (Dana) are capable of entering a resting state called quiescence to overcome adverse environmental conditions. Although physiological changes associated with this transition have been described, the molecular mechanisms are thus far...... for ferritin during the recovery phase toward hatching. This suggests that ferritin is a protein needed when embryos of A. tonsa enter quiescence. Both hsp70 and ferritin are required during recovery from quiescent to subitaneous state when embryogenesis continues toward egg hatching....

Larval development ratio test with the calanoid copepod Acartia tonsa as a new bioassay to assess marine sediment quality.

Science.gov (United States)

Buttino, Isabella; Vitiello, Valentina; Macchia, Simona; Scuderi, Alice; Pellegrini, David

2018-03-01

The copepod Acartia tonsa was used as a model species to assess marine sediment quality. Acute and chronic bioassays, such as larval development ratio (LDR) and different end-points were evaluated. As a pelagic species, A. tonsa is mainly exposed to water-soluble toxicants and bioassays are commonly performed in seawater. However, an interaction among A. tonsa eggs and the first larval stages with marine sediments might occur in shallow water environments. Here we tested two different LDR protocols by incubating A. tonsa eggs in elutriates and sediments coming from two areas located in Tuscany Region (Central Italy): Livorno harbour and Viareggio coast. The end-points analyzed were larval mortality (LM) and development inhibition (DI) expressed as the percentage of copepods that completed the metamorphosis from nauplius to copepodite. Aims of this study were: i) to verify the suitability of A. tonsa copepod for the bioassay with sediment and ii) to compare the sensitivity of A. tonsa exposed to different matrices, such as water and sediment. A preliminary acute test was also performed. Acute tests showed the highest toxicity of Livorno's samples (two out of three) compared to Viareggio samples, for which no effect was observed. On the contrary, LDR tests with sediments and elutriates revealed some toxic effects also for Viareggio's samples. Results were discussed with regards to the chemical characterization of the samples. Our results indicated that different end-points were affected in A. tonsa, depending on the matrices to which the copepods were exposed and on the test used. Bioassays with elutriates and sediments are suggested and LDR test could help decision-makers to identify a more appropriate management of dredging materials. Copyright © 2017 Elsevier Inc. All rights reserved.

Microplastic potentiates triclosan toxicity to the marine copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Syberg, Kristian; Nielsen, Anne; Khan, Farhan

2017-01-01

Microplastics (MP) are contaminants of environmental concern partly due to plastics ability to sorb and transport hydrophobic organic contaminants (HOC). The importance of this "vector effect" is currently being debated in the scientific community. This debate largely ignores that the co-exposure......Microplastics (MP) are contaminants of environmental concern partly due to plastics ability to sorb and transport hydrophobic organic contaminants (HOC). The importance of this "vector effect" is currently being debated in the scientific community. This debate largely ignores that the co......-exposures of MP and HOC are mixtures of hazardous agents, which can be addressed from a mixture toxicity perspective. In this study, mixture effects of polyethylene microbeads (MP) and triclosan (TCS) (a commonly used antibacterial agent in cosmetics) were assessed on the marine copepod Acartia tonsa. Data...... indicated that MP potentiate the toxicity of TCS, illustrating the importance of understanding the mixture interaction between plastics and HOC when addressing the environmental importance of the vector effect....

The constraints of high density production of the calanoid copepod Acartia tonsa Dana

DEFF Research Database (Denmark)

Vu, Minh T. T.; Hansen, Benni W.; Kiørboe, Thomas

2017-01-01

studied and aquaculture relevant calanoid Acartia tonsa. A simple model was developed to evaluate the influence of individual egg production, egg predation, crowding effects and tank design on the egg harvest. At high densities from 500 to 3500 ind L−1, there was no difference in food ingestion and egg...... cannibalism. However, the copepods showed lower food consumption and egg cannibalism compared to the ecologically relevant densities of 20–100 ind L−1. Model calculations demonstrate that maximum egg harvest is the result of a subtle balance between water mixing and tank depth: a shallow, non-mixed tank...... will allow the eggs to settle and escape cannibalism but at the same time prevent the algal food staying suspended, and full utilization of the egg production potential depends on the fine tuning of these parameters...

Toxicity of nickel in the marine calanoid copepod Acartia tonsa: Nickel chloride versus nanoparticles.

Science.gov (United States)

Zhou, C; Vitiello, V; Casals, E; Puntes, V F; Iamunno, F; Pellegrini, D; Changwen, W; Benvenuto, G; Buttino, I

2016-01-01

Nickel compounds are widely used in industries and have been massively introduced in the environment in different chemical forms. Here we report the effect of two different chemical forms of nickel, NiCl2 and nickel nanoparticles (NiNPs), on the reproduction of the marine calanoid copepod Acartia tonsa. The behavior of nickel nanoparticles was analyzed with different techniques and with two protocols. In the "sonicated experiment" (SON) NiNP solution was sonicated while in the "non-sonicated experiment" (NON-SON) the solution was vigorously shaken by hand. Final nominal concentrations of 5, 10 and 50mgL(-1) and 1, 5 and 10mgL(-1) NiNPs were used for the acute and semichronic tests, respectively. Nanoparticle size did not change over time except for the highest concentration of 50mgL(-1) NiNPs, in which the diameter increased up to 843nm after 48h. The concentration of Ni dissolved in the water increased with NP concentration and was similar for SON and NON-SON solutions. Our results indicate that sonication does not modify toxicity for the copepod A. tonsa. Mean EC50 values were similar for NON-SON (20.2mgL(-1)) and SON experiments (22.14mgL(-1)) in the acute test. Similarly, no differences occurred between the two different protocols in the semichronic test, with an EC50 of 7.45mgL(-1) and 6.97mgL(-1) for NON-SON and SON experiments, respectively. Acute and semichronic tests, conducted exposing A. tonsa embryos to NiCl2 concentrations from 0.025 to 0.63mgL(-1), showed EC50 of 0.164 and 0.039mgL(-1), respectively. Overall, A. tonsa is more sensitive to NiCl2 than NiNPs with EC50 being one order of magnitude higher for NiNPs. Finally, we exposed adult copepods for 4 days to NiCl2 and NiNPs (chronic exposure) to study the effect on fecundity in terms of daily egg production and naupliar viability. Egg production is not affected by either form of nickel, whereas egg viability is significantly reduced by 0.025mgL(-1) NiCl2 and by 8.5mgL(-1) NiNPs. At NiNP concentration

Long-term decline in the calanoid copepod Acartia tonsa in central Chesapeake Bay, USA: An indirect effect of eutrophication?

Science.gov (United States)

Kimmel, David G.; Boynton, Walter R.; Roman, Michael R.

2012-04-01

A long-term abundance record of the calanoid copepod Acartia tonsa in the Maryland portion of Chesapeake Bay was compiled from 1966 to 2002. A significant downward trend in the summertime abundance of Acartia tonsa was found in central Chesapeake Bay. We propose that environmental and food web changes occurred as the Chesapeake Bay became increasingly impacted by human activity which eventually led to the overall decline of A. tonsa. Environmental changes included a long-term rise in water temperature and the volume of hypoxic water during the summer. These changes occurred during the same time period as increases in chlorophyll a concentration, declines in the landings of the eastern oyster Crassostrea virginica, and declines in abundance of the sea nettle Chrysaora quinquecirrha. A CUSUM analysis showed that each time-series experienced a change point during over the past 50 years. These changes occurred sequentially, with chlorophyll a concentration increasing beginning in 1969, water temperature and hypoxic volume increasing beginning in the early 1980s, more recent Maryland C. virginica landings begin declining in the early 1980s and A. tonsa and C. quinquecirrha declining starting in 1989. A stepwise regression analysis revealed that the reduction in A. tonsa abundance appeared to be most associated with a decreasing trend in C. quinquecirrha abundance, though only when trends in the two time-series were present. The drop in C. quinquecirrha abundance is associated with reduced predation on the ctenophore, Mnemiopsis leidyi, a key predator of A. tonsa. The long-term decline of A. tonsa has likely impacted trophic transfer to fish, particularly the zooplanktivorous bay anchovy (Anchoa mitchilli). A time-series of bay anchovy juvenile index showed a negative trend and the CUSUM analysis revealed 1993 as its starting point. Total fisheries landings, excluding menhaden (Brevoortia tyrannus), in Chesapeake Bay have also declined during the same period and this

First feeding of Eugerres brasilianus (Carapeva larvae with Acartia tonsa (Copepod nauplii increases survival and resistance to acute stress

Directory of Open Access Journals (Sweden)

Wanessa de Melo Costa

2016-01-01

Full Text Available The rotifer Brachionus sp. is commonly used for larval feeding in marine fish hatcheries. The aim of this study was to evaluate whether the inclusion of Acartia tonsa nauplii in the initial diet of carapeva larvae improves their survival, growth and resistance to stress when compared to the regimen containing only rotifers. Adult copepods were collected in the wild and cultured with the microalgae Chaetoceros muelleri, Isochrysis galbana and Nannochloropsis oculata to obtain nauplii. Carapeva larvae were grown for 15 days using four treatments and three replicates: 1 Brachionus plicatilis rotifers (10 to 15/mL; 2 A. tonsa nauplii (0.25 to 0.5/mL; 3 Brachionus plicatilis rotifers (5 to 7.5/mL + A. tonsa nauplii (0.12 to 0.25/mL, and 4 no supply of live feed. After 15 days, the carapeva larvae were subjected to stress by exposure to air for 10 seconds and then returned to the source tank to evaluate survival after 24 h. Survival and stress resistance were higher in carapeva larvae fed B. plicatilis + A. tonsa nauplii (P<0.05, 20.9 ± 11.2% and 88.9%, respectively. These results confirm the positive effect of the inclusion of copepod nauplii in the diet of fish larvae. However, more research is needed to validate these results.

Environmental stress responses and experimental handling artifacts of a model organism, the copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Nilsson, Birgitte; Jepsen, Per Meyer; Bucklin, Ann

2018-01-01

Handling animals during experiments potentially affects the differential expression of genes chosen as biomarkers of sub-lethal stress. RNA sequencing was used to examine whole-transcriptome responses caused by laboratory handling of the calanoid copepod, Acartia tonsa. Salinity shock (S=35 to S=...... studies can lead to inaccurate conclusions. The present study provides a baseline for studying handling stress in future studies using this model organism and others....... for these genes between 15 min and 24 h following exposure. Since handling stress clearly affects transcriptional patterns, it is important to consider handling when designing experiments, by either including additional controls or avoiding focus on impacted genes. Not considering handling in gene expression...

Resting egg production induced by food limitation in the calanoid copepod Acartia tonsa

DEFF Research Database (Denmark)

Drillet, Guillaume; Hansen, Benni W.; Kiørboe, Thomas

2011-01-01

Three populations of the copepod Acartia tonsa, two from the Baltic Sea and one from the U.S. East Coast, were compared for resting egg production at conditions of saturating and limiting food availability. All three populations produced eggs that hatched within 72 h when incubated at 17°C...... (subitaneous eggs), but the two Baltic populations in addition produced eggs that hatched at a much slower rate, in the course of a month (delayed hatching eggs [DHE]). Such eggs were not produced by the U.S. population. The fraction of DHE increased when food was limiting. Females from a Baltic population...... that were incubated individually all produced subitaneous eggs, but about half the females consistently also produced DHE. Cold storage that mimicked boreal winter conditions synchronized the hatching of DHE after extended storage, indicating that spring hatching of DHE might seed the water column...

Ecological effects of scrubber water discharge on coastal plankton: Potential synergistic effects of contaminants reduce survival and feeding of the copepod Acartia tonsa

DEFF Research Database (Denmark)

Koski, Marja; Stedmon, Colin; Trapp, Stefan

2017-01-01

and hydrocarbons. We investigated 1) the threshold concentrations of scrubber discharge water for survival, feeding and reproduction of the copepod Acartia tonsa, 2) whether the effects depend on the exposure route and 3) whether exposure to discharge water can be detected in field-collected organisms. A direct...... constituents could have synergistic effects on plankton productivity and bioaccumulation of metals, although the effects will depend on their dilution in the marine environment....

Could some procedures commonly used in bioassays with the copepod Acartia tonsa Dana 1849 distort results?

Science.gov (United States)

Lopes, Laís Fernanda de Palma; Agostini, Vanessa Ochi; Muxagata, Erik

2018-04-15

Many organizations have suggested the use of the Calanoid copepod Acartia tonsa in protocols for acute toxicity tests. Nevertheless, these protocols present some problems, such as using 60-180µm meshes to separate specific stages of A. tonsa or carrying out the tests using small volumes that reflect high densities of A. tonsa that do not occur in nature, which could lead to distorted results. In addition, ecotoxicological studies may use statistical approaches that are inadequate for the type of data being analysed. For these reasons, some methodological approaches for bioassays using A. tonsa need to be clarified and revised. In this study, we present information about (i) the retention of copepodite stages of A. tonsa on 180, 330 and 500µm net meshes; (ii) tested storage volumes of 1 organism per 5, 10 or 20mL in each test container (TC); and (iii) considerations about the statistics employed. The results demonstrated that a net mesh of 180µm is capable of retaining all copepodite stages (CI to CVI), contrasting with the recommendation of using a 180µm mesh to separate out adults only. Coarser meshes (330 and 500µm) can also retain different proportions of all copepodite stages, but cannot separate out one developmental stage only. Twenty-five millilitres of medium in an open TC, commonly employed in bioassays simulating densities of 1 organism 5mL -1 , completely evaporated, and the results showed that the TCs need to be covered (e.g., PVC film) and filled with a minimum of 100mL of culture medium (simulating densities of 1 organism 20mL -1 ) to avoid evaporation and increases in salinity. The current use of ANOVA in ecotoxicological studies with proportions of surviving organisms should also be reconsidered since the data are discrete and have a binomial distribution; general linear models (GLMs) are considered more adequate. The information presented here suggests some adjustments that hopefully will enable the improvement of the procedures and methods

Improving cold storage of subitaneous eggs of the copepod Acartia tonsa Dana from the Gulf of Mexico (Florida, USA)

DEFF Research Database (Denmark)

Drillet, Guillaume; Lindley, L.C.; Michels, A.

2007-01-01

(kanamycin sulphate and oxytetracycline HCl) on extending the shelf life of cold-stored subitaneous Acartia tonsa eggs. Also, egg development effects on the survival of the eggs were tested. Glucose did not have any significant effects on the survival of the eggs. However, the addition of antibiotics......%. However, long exposure to high concentrations of antibiotics was lethal to the copepod eggs. After more than 30 days of exposure to 100 mg L-1 of oxytetracycline, the survival of the eggs was lower than in the untreated samples. After 45 days, oxytetracycline-treated eggs (100 mg L-1) presented a hatching...

Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes.

Science.gov (United States)

Wolfram, Stefanie; Nejstgaard, Jens C; Pohnert, Georg

2014-01-01

Polyunsaturated aldehydes (PUAs) are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the α,β,γ,δ-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies.

Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes.

Directory of Open Access Journals (Sweden)

Stefanie Wolfram

Full Text Available Polyunsaturated aldehydes (PUAs are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the α,β,γ,δ-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies.

Effect of temperature and viscosity on swimming velocity of the copepod Acartia tonsa, brine shrimp Artemia salina and rotifer Brachionus plicatilis

DEFF Research Database (Denmark)

Larsen, Poul Scheel; Madsen, C.V.; Riisgard, H.U.

2008-01-01

Beating cilia are important organelles for swimming in many zooplanktonic aquatic organisms, including many invertebrate larvae, rotifers and ciliates, but other planktonic organisms, such as copepods and brine shrimps, use muscle-powered swimming appendages. In recent studies we found...... of swimming velocity for a 10 degrees C temperature reduction) that is found to be largest for the brine shrimp Artemia salina nauplius (37 %) and the rotifer Brachionus plicatilis (26%), but negligible for the copepod Acartia tonsa (4%). We suggest that experimental data on change in swimming velocity (V......) due to change in kinematic viscosity (v) be correlated in terms of a power law, V proportional to v(-m). The present data on swimming velocity of copepods, brine shrimps and rotifers show values of exponent m approximate to 1.5 to 3, with a trend of decreasing values for increasing size of species...

Collection and cultivation methods of Acartia tonsa for toxicity testing

International Nuclear Information System (INIS)

Hood, C.A.; Mayo, R.R.

1995-01-01

Acartia tonsa were located and collected from Galveston Bay, Texas in June 1995, using plankton nets and transported to the laboratory for culture. After literature searching and laboratory experimentation. A simple reliable method was designed to culture A. tonsa. This method requires a minimum of glassware and supplies. Adult A. tonsa are placed in one gallon bell jars filled with natural seawater. The jars are then maintained in a water bath at a constant temperature. Water changes are conducted twice weekly and organisms are fed daily with a mixture of algae, Skeletonema costatum, isocrysis galbana, and Thalassiosira sp. Gravid females are then isolated in generators for 24 hours to obtain known age neonates. The neonates are maintained up to a specific age and then are used in toxicity tests such as the ''Determination of the Acute Lethal Toxicity to Marine Copepods,'' required in the United Kingdom for all chemicals used for offshore drilling fluid applications

Comparative oxygen consumption rates of subitaneous and delayed hatching eggs of the calanoid copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Hansen, Benni Winding; Drillet, Guillaume

2013-01-01

nanorespirometry to monitor initial oxygen consumption rate of individual eggs of the ubiquitous neritic calanoid copepod Acartia tonsa to distinguish between subitaneous and DHE. We hypothesized that subitaneous eggs exhibit higher initial oxygen consumption rates than DHE, and that initial egg oxygen consumption...... rate is correlated to the time for the individual egg to hatch. Subitaneous eggs exhibited higher initial oxygen consumption rates than DHE and there were no pattern in initial oxygen consumption rates vs. time to hatch or die from the eggs. Variability in initial oxygen consumption rates within...... batches of both subitaneous and DHE, as well as between these egg types, is prevalent. There was a continuum from sluggish- to fast metabolising eggs considering initial oxygen consumption rates most likely reflecting phenotypic variation within cohorts. No matter the individual initial egg oxygen...

Food size spectra, ingestion and growth of the copepod Acartia tonsa during development: implications for the determination of copepod production

DEFF Research Database (Denmark)

Berggren, U.; Hansen, B.; Kiørboe, Thomas

1988-01-01

Clearance rates on different sizes of spherically shaped algae were determined in uni-algal experiments for all developmental stages (NII through adult) of the copepodAcartia tonsa, and used to construct food size spectra. Growth and developmental rates were determined at 7 food levels (0 to 1 500...... g C l-1 ofRhodomonas baltica). The lower size limit for particle capture was between 2 and 4 m for all developmental stages. Optimum particle size and upper size limit increased during development from 7 m and 10 to 14 m for NII to NIII to 14 to 70 m and 250 m for adults, respectively. When food...... size spectra were normalized (percent of maximum clearance in a particular stage versus particle diameter/prosome length) they resembled log-normal distributions with near constant width (variance). Optimum, relative particle sizes corresponded to 2 to 5% of prosome length independent of developmental...

Effects of adult stocking density on egg production and viability in cultures of the calanoid copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Jepsen, Per Meyer; Andersen, Nikolaj; Holm, Thue

2007-01-01

was 84.7±4.8% and was never observed below 76.1%, with no significant differences across the stocking densities. Conclusively, as a practical recommendation for the aquaculture industry, copepod cultures with densities ranging from 100 to 600 adults L−1 and presumably even more dense cultures......The effect of stocking density of the calanoid copepod Acartia tonsa was evaluated in a 96 h rearing experiment. Possible density-dependent egg production and egg viability were analysed at stocking densities of 100, 200, 300, 400 and 600 adults L−1. Temperature, oxygen saturation and algal...... concentration were kept optimal. A non-density-dependent mortality rate of 15–19% day−1 was documented. A non-significant density-dependent egg production was observed between 100 and 600 adults L−1. The average egg production was 22.5±8.8 egg female−1 day−1 in all densities. The average egg hatching success...

Effect of 2,4-dihydroxybenzophenone (BP1) on early life-stage development of the marine copepod Acartia tonsa at different temperatures and salinities

DEFF Research Database (Denmark)

Kusk, Kresten Ole; Avdolli, Manola; Wollenberger, Leah

2011-01-01

a copepodite stage (DT(½) ) at the different conditions were calculated. The DT(½) values decreased from 296 h at 15°C to 89 h at 25°C and were also affected by salinity (126 h at 15‰ and 167 h at 30‰), whereas the light:dark regime and culture density influenced development only to a minor extent. BP1......Benzophenone (BP)-type ultraviolet (UV) filters are widely used in cosmetic and sunscreen products and can enter the aquatic environment. Therefore, we investigated the subchronic toxicity of 2,4-dihydroxybenzophenone (BP1) on the marine calanoid copepod Acartia tonsa in an early life......-stage development study. Since developmental endpoints depend on environmental conditions, a preceding study of A. tonsa development was performed at three temperatures, four salinities, four light:dark regimes, six food densities, and four culture densities. Times elapsed until 50% of the population had reached...

Ecological effects of scrubber water discharge on coastal plankton: Potential synergistic effects of contaminants reduce survival and feeding of the copepod Acartia tonsa.

Science.gov (United States)

Koski, Marja; Stedmon, Colin; Trapp, Stefan

2017-08-01

To meet the oncoming requirements for lower sulphur emissions, shipping companies can install scrubbers where the exhaust is sprayed with seawater and subsequently discharged to the sea. The discharge water has a pH around 3 and contains elevated concentrations of vanadium, nickel, lead and hydrocarbons. We investigated 1) the threshold concentrations of scrubber discharge water for survival, feeding and reproduction of the copepod Acartia tonsa, 2) whether the effects depend on the exposure route and 3) whether exposure to discharge water can be detected in field-collected organisms. A direct exposure to discharge water increased adult copepod mortality and reduced feeding at metal concentrations which were orders of magnitude lower than the lethal concentrations in previous single-metal studies. In contrast, reproduction was not influenced by dietary uptake of contaminants. Scrubber water constituents could have synergistic effects on plankton productivity and bioaccumulation of metals, although the effects will depend on their dilution in the marine environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inclusion of copepod Acartia tonsa nauplii in the feeding of Centropomus undecimalis larvae increases stress resistance

Directory of Open Access Journals (Sweden)

Wanessa de Melo-Costa

2015-09-01

Full Text Available This research represents the first result of studies of the common snook Centropomus undecimalis larvae from broodstock matured in captivity in Brazil. The aim of this study was to evaluate if the inclusion of Acartia tonsa nauplii improves stress resistance of common snook larvae. The larvae were fed with: rotifers Brachionus plicatilis (10 to 15 mL-1; A. tonsa nauplii (0.25 to 0.5 mL-1 and rotifers (5 to 7.5 mL-1, and A. tonsa nauplii (0.12 to 0.25 mL-1. The average percentage of survival of the treatments was 11.9%. At 20 days of age, larvae were subjected to thermal stress. Subsequently, the stress resistance was evaluated. Common snook larvae fed B. plicatilis+A. tonsa reached a higher weight and length (7.5 ± 0.00 mg and 9.1 ± 0.23 mm, respectively and resisted more heat stress (87.4% than larvae fed other foods, indicating that the feed mixture is satisfactory as a starter diet for larvae of common snook. However, more research is needed to confirm these results.

Effects of salinity, commercial salts, and water type on cultivation of the cryptophyte microalgae Rhodomonas salina and the calanoid Copepod Acartia tonsa

DEFF Research Database (Denmark)

Jepsen, Per Meyer; Thoisen, Christina V.; Carron-Cabaret, Thibaut

2018-01-01

Marine aquaculture facilities positioned far from the sea need access to seawater (SW); hence, commercial salts are often the chosen solution. In marine hatcheries, most fish larvae require live feed (zooplankton) that are in turn fed with microalgae. The objective of this research was to investi......Marine aquaculture facilities positioned far from the sea need access to seawater (SW); hence, commercial salts are often the chosen solution. In marine hatcheries, most fish larvae require live feed (zooplankton) that are in turn fed with microalgae. The objective of this research...... was to investigate the applicability of commercial salts and clarify the potential effects on the cultivation of the microalga Rhodomonas salina and the copepod Acartia tonsa. Three commercial salts were tested, Red Sea Salt (RS), Red Sea – Coral Pro Salt (CP), and Blue Treasure Salt. R. salina was cultured...

First genetic quantification of sex- and stage-specific feeding in the ubiquitous copepod Acartia tonsa

DEFF Research Database (Denmark)

Ismar, Stefanie M.H.; Kottmann, Johanna Sarah; Sommer, Ulrich

2018-01-01

-specific feeding differences between Acartia life stages and sexes, which can have implications on food-web dynamics and specific nutrient transfer to higher trophic levels in copepod populations of varying age composition under changing environmental parameters, such as rising temperatures and increasing ocean...... acidification....

Effects of anti-androgens cyproterone acetate, linuron, vinclozolin, and p,p'-DDE on the reproductive organs of the copepod Acartia tonsa.

Science.gov (United States)

Watermann, Burkard T; Albanis, Triantafyllos A; Galassi, Silvana; Gnass, Katarina; Kusk, Kresten O; Sakkas, Vasilios A; Wollenberger, Leah

2016-11-09

The study was performed to detect the effects of anti-androgenic compounds on the reproduction. In this paper alterations observed in the marine calanoid copepod Acartia tonsa exposed to environmental concentrations of cyproterone acetate (CPA), linuron (LIN), vinclozolin (VIN), and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) for 21 days covering a full life cycle are described. Histological alterations were studied with a focus on reproductive organs, gonad and accessory sexual glands. Exposure to ≥1.2 µg L(-1) CPA caused degeneration of spermatocytes and deformation of the spermatophore in males. In a single male exposed to 33 µg L(-1) CPA, an ovotestis was observed. In CPA exposed females, enhancement of oogenesis, increase in apoptosis and a decrease in proliferation occurred. Exposure of males to ≥12 µg L(-1) LIN caused degenerative effects in spermatogonia, spermatocytes and spermatids, and at 4.7 µg L(-1) LIN, the spermatophore wall displayed an irregular formation. In LIN exposed females, no such structural alterations were found; however, the proliferation index was reduced at 29 µg L(-1) LIN. At an exposure concentration of ≥100 µg L(-1) VIN, distinct areas in male gonad were stimulated, whereas others displayed a disturbed spermatogenesis and a deformed spermatophore wall. In VIN exposed female A. tonsa, no effects were observed. Male A. tonsa exposed to p,p'-DDE displayed an impairment of spermatogenesis in all stages with increased degrees of apoptosis. In p,p'-DDE-exposed females, a statistical significant increase of the proliferation index and an intensification of oogenesis were observed at 0.0088 µg L(-1).

Influence of two different green algal diets on specific dynamic action and incorporation of carbon into biochemical fractions in the copepod Acartia tonsa

DEFF Research Database (Denmark)

Thor, P.; Cervetto, G.; Besiktepe, S.

2002-01-01

Previous studies have shown that the two green algae Tetraselmis sp. (Prasinophyceae) and Dunaliella tertiolecta (Chlorophyceae) induce high and low egg production rates in Acartia tonsa. The primary goal of the present study was to investigate if this is attributable to differences in the specif...

Environmental Stress Responses and Experimental Handling Artifacts of a Model Organism, the Copepod Acartia tonsa (Dana

Directory of Open Access Journals (Sweden)

Birgitte Nilsson

2018-05-01

Full Text Available Handling animals during experiments potentially affects the differential expression of genes chosen as biomarkers of sub-lethal stress. RNA sequencing was used to examine whole-transcriptome responses caused by laboratory handling of the calanoid copepod, Acartia tonsa. Salinity shock (S = 35 to S = 5 was used as positive stress control; individuals not exposed to handling or other stressors served as negative stress control. All copepods were grown from eggs to adults without being handled or exposed to any stressors prior the experiment. Survival of nauplii and adults was estimated for up to 10 min of exposure to handling stress and salinity shock. Only adults exhibited decreased survival (44 ± 7% with 10 min of exposure in response to handling stress and were selected for definitive experiments for RNA sequencing. After 10 min of experimental exposures to handling stress or salinity shock, adults were incubated for 15 min or 24 h at normal culture conditions. A small number of significantly differentially expressed genes (DEGs were observed 15 min after exposure to handling stress (2 DEGs or salinity shock (7 DEGs. However, 24 h after exposure, handling stress resulted in 276 DEGs and salinity shock resulted in 573 DEGs, of which 174 DEGs were overlapping between the treatments. Among the DEGs observed 24 h after exposure to handling stress or salinity shock, some commonly-used stress biomarkers appeared at low levels. This suggests that a stress-response was induced at the transcriptional level for these genes between 15 min and 24 h following exposure. Since handling stress clearly affects transcriptional patterns, it is important to consider handling when designing experiments, by either including additional controls or avoiding focus on impacted genes. Not considering handling in gene expression studies can lead to inaccurate conclusions. The present study provides a baseline for studying handling stress in future studies using this

Egg production and hatching success of Calanus chilensis and Acartia tonsa in the northern Chile upwelling zone (23°S), Humboldt Current System

Science.gov (United States)

Ruz, Paula M.; Hidalgo, Pamela; Yáñez, Sonia; Escribano, Rubén; Keister, Julie E.

2015-08-01

Oxygen Minimum Zones (OMZ's) are expanding and intensifying as result of climate change, affecting Eastern Boundary Upwelling Systems. Local effects of vertical movements of OMZ's that result from changes in upwelling intensity could reduce or expand the oxygenated surface layer that most zooplanktonic species inhabit in coastal areas. Using the copepods Calanus chilensis and Acartia tonsa as model organisms, an experimental test of the impact of different dissolved oxygen (DO) concentrations (between 0.5 and 5 ml L- 1) on egg production and hatching success was carried out and compared with field estimations of egg production, female and egg abundance in Mejillones Bay (23°S). Abundance of C. chilensis was highly variability and no consistent pattern in egg production and hatching success was found across DO levels, whereas A. tonsa egg production had maximum values between 2.6 and 4.7 ml O2 L- 1 and hatching success was positively correlated with DO (r = 0.75). In the field, temperature was the main factor controlling the dynamics of both species, while Chl-a and DO were also correlated with C. chilensis and A. tonsa, respectively. Principal Component Analysis showed that abundances of both copepods were controlled by temperature, stratification, OMZ depth, and Ekman transport, which together explained more than 70% of the total variance and were the main factors that modulated the populations of C. chilensis and A. tonsa in the upwelling zone of northern Chile (23°S). The differential responses of C. chilensis and A. tonsa to changes in DO concentrations associated with vertical movements of the OMZ suggest that C. chilensis may be better adapted to hypoxic conditions than A. tonsa, however both species are successful and persistent all year-round. We suggest that physiological responses of copepods could be used to evaluate population dynamics affected by the shoaling of OMZ's and the repercussions to trophic food webs of eastern boundary current systems.

Development of copepod nauplii to copepodites

DEFF Research Database (Denmark)

Andersen, Henrik Rasmus; Wollenberger, Leah; Halling-Sørensen, Bent

2001-01-01

Test compounds including natural hormones, endocrine disrupters, environmentally occurring compounds, and reference compounds were tested for acute toxicity and inhibitory effect on larval development in the copepod Acartia tonsa. Three compounds, 17a-ethinylestradiol, p-octylphenol, and tamoxifen...

Can we use laboratory reared copepods for experiments - a comparison of feeding behavior and reproduction between a field and a laboratory population of Acartia tonsa

DEFF Research Database (Denmark)

Tiselius, P.; Hansen, B.; Jonsson, P.

1995-01-01

Motility patterns and egg production were investigated in two populations of Acartia tonsa, field animals from the Oresund and laboratory animals from a 12-year-old (approximate to 120 generations) culture. When observed in aquaria with a layer of Thalassiosira weissflogii in the middle, laboratory...... differed considerably from held-caught A. tonsa from the eastern United States, where both behaviour and egg production changed consistently and in accordance with a strong aggregation in food patches. (C) 1995 International Council for the Exploration of the Sea...

Do Acartia tonsa (Dana) eggs regulate their volume and osmolality as salinity changes?

DEFF Research Database (Denmark)

Hansen, Benni Winding; Drillet, Guillaume; Pedersen, Morten Foldager

2012-01-01

Subitaneous eggs from an euryhaline calanoid copepod Acartia tonsa were challenged by changes in salinity within the range from full strength salinity, down to zero and up to >70 psu. Egg volume changed immediately, increasing from 2.8 × 105 μm3 at full strength salinity (35 psu) to 3.8 × 105 μm3...... at 0 psu and back to its initial volume when gradually being returned to full strength salinity. Egg osmolality followed the molality of the surrounding water when challenged within a salinity range from 2 to 50 psu. Egg respiration was not affected when eggs kept at 35 psu was exposed to low salinity...... (2 psu). These results suggest that eggs are unable to regulate their volume or osmolality when challenged with changes in salinity. Gradual changes in salinity from 35 to 2 psu and back did not harm the eggs (embryos), since the hatching success remained unaffected by such changes in salinity...

Copepods' Response to Burgers' Vortex: Deconstructing Interactions of Copepods with Turbulence.

Science.gov (United States)

Webster, D R; Young, D L; Yen, J

2015-10-01

This study examined the behavioral response of two marine copepods, Acartia tonsa and Temora longicornis, to a Burgers' vortex intended to mimic the characteristics of a turbulent vortex that a copepod is likely to encounter in the coastal or near-surface zone. Behavioral assays of copepods were conducted for two vortices that correspond to turbulent conditions with mean dissipation rates of turbulence of 0.009 and 0.096 cm(2) s(-3) (denoted turbulence level 2 and level 3, respectively). In particular, the Burgers' vortex parameters (i.e., circulation and rate of axial strain rate) were specified to match a vortex corresponding to the median rate of dissipation due to viscosity for each target level of turbulence. Three-dimensional trajectories were quantified for analysis of swimming kinematics and response to hydrodynamic cues. Acartia tonsa did not significantly respond to the vortex corresponding to turbulence level 2. In contrast, A. tonsa significantly altered their swimming behavior in the turbulence-level-3 vortex, including increased relative speed of swimming, angle of alignment of the trajectory with the axis of the vortex, ratio of net-to-gross displacement, and acceleration during escape, along with decreased turn frequency (relative to stagnant control conditions). Further, the location of A. tonsa escapes was preferentially in the core of the stronger vortex, indicating that the hydrodynamic cue triggering the distinctive escape behavior was vorticity. In contrast, T. longicornis did not reveal a behavioral response to either the turbulence level 2 or the level 3 vortex. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon.

Science.gov (United States)

Picone, Marco; Bergamin, Martina; Delaney, Eugenia; Ghirardini, Annamaria Volpi; Kusk, Kresten Ole

2018-01-01

The early-life stages of development of the calanoid copepod Acartia tonsa from egg to copepodite I is proposed as an endpoint for assessing sediment toxicity by exposing newly released eggs directly onto the sediment-water interface. A preliminary study of 5 sediment samples collected in the lagoon of Venice highlighted that the larval development rate (LDR) and the early-life stages (ELS) mortality endpoints with A. tonsa are more sensitive than the standard amphipod mortality test; moreover LDR resulted in a more reliable endpoint than ELS mortality, due to the interference of the sediment with the recovery of unhatched eggs and dead larvae. The LDR data collected in a definitive study of 48 sediment samples from the Venice Lagoon has been analysed together with the preliminary data to evaluate the statistical performances of the bioassay (among replicate variance and minimum significant difference between samples and control) and to investigate the possible correlation with sediment chemistry and physical properties. The results showed that statistical performances of the LDR test with A. tonsa correspond with the outcomes of other tests applied to the sediment-water interface (Strongylocentrotus purpuratus embryotoxicity test), sediments (Neanthes arenaceodentata survival and growth test) and porewater (S. purpuratus); the LDR endpoint did, however, show a slightly higher variance as compared with other tests used in the Lagoon of Venice, such as 10-d amphipod lethality test and larval development with sea urchin and bivalves embryos. Sediment toxicity data highlighted the high sensitivity and the clear ability of the larval development to discriminate among sediments characterized by different levels of contamination. The data of the definitive study evidenced that inhibition of the larval development was not affected by grain-size and the organic carbon content of the sediment; in contrast, a strong correlation between inhibition of the larval development

Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, Acartia tonsa: a laboratory study

Science.gov (United States)

Shayegan, Majid; Esmaeili Fereidouni, Abolghasem; Agh, Naser; Jani Khalili, Khosrow

2016-07-01

The effects of salinity on the copepod, Acartia tonsa in terms of daily egg production rate (EPR), hatching success, fecal pellet production rate (FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods (seven consecutive days). Results show EPR was affected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females (long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages (56.7% and 52.2%, respectively) were significantly observed at two salinities of 13 and 20 compared to that at 35 (25%). Total longevity of females was not affected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

Embryonic cold storage capability from seven strains of Acartia spp. isolated in different geographical areas

DEFF Research Database (Denmark)

Hansen, Benni Winding; Buttino, Isabella; Cunha, Maria Emilia

2016-01-01

practically for establishing an egg bank, where embryos can be kept alive and hatched at a later time. The stored embryos can be shipped to end-users and the hatched nauplii used directly as live feed as well as they can be used to establish new copepod cultures. Acartia tonsa (Dana) is a cosmopolite...

Influence of swimming behavior of copepod nauplii on feeding of larval turbot (Scophthalmus maximus)

DEFF Research Database (Denmark)

Bruno, Eleonora; Højgaard, Jacob Kring; Hansen, Benni Winding

2018-01-01

Feeding in larval fish is influenced by a range of factors and among these are the morphological and behavioral characteristics of their prey. We investigated the influence of the swimming behavior of two species of calanoid copepods, Acartia tonsa and Temora longicornis, on larval turbot feeding....... The nauplii of these species represent two contrasting swimming behaviors: A. tonsa is a jump-sink type swimmer, while T. longicornis is a cruise swimming type. Three replicates of ten larvae aged 7 and 9 days post hatch (DPH) were observed feeding on one of the two copepod species using a 2-dimensional video...

Copepod swimming behavior, respiration, and expression of stress-related genes in response to high stocking densities

DEFF Research Database (Denmark)

Nilsson, Birgitte; Jakobsen, Hans Henrik; Stief, Peter

2017-01-01

is problematic for calanoid copepod species like Acartia tonsa. In the present study, we evaluated the response of copepods experiencing stress under high-density conditions by assessing the acute stress level of A. tonsa. Control density was at 100 ind. L−1 while the treatments were increased stepwise up to 10......,000 ind. L−1. Three biological/physiological end-points were studied: swimming behavior, respiration rate and expression level of stress-related genes. None of the elevated densities caused any significant change in swimming behavior, respiration rate or gene expression level. This study suggests...... that adults of A. tonsa do not exhibit any measurable acute stress response when exposed to high culture densities for 12 h....

Foraging response and acclimation of ambush feeding and feeding-current feeding copepods to toxic dinoflagellates

DEFF Research Database (Denmark)

Xu, Jiayi; Nielsen, Lasse Tor; Kiørboe, Thomas

2018-01-01

reticulatum. We hypothesize (1) that ambush feeders are less affected by toxic algae than feeding-current feeders, (2) that copepods acclimate to the toxic algae, and (3) that phytoplankton cells previously exposed to copepod cues elicit stronger responses. Both copepod species consumed the toxic algae...... to examine the response and temporal acclimation (5 d) of two copepods with different foraging behaviors to toxic dinoflagellates. Feeding-current feeding Temora longicornis and ambush feeding Acartia tonsa were offered three strains of toxic Alexandrium tamarense and a nontoxic control Protoceratium...... at a reduced rate and there was no difference in their net-response, but the mechanisms differed. T. longicornis responded in strain-specific ways by reducing its feeding activity, by rejecting captured algae, or by regurgitating consumed cells. A. tonsa reduced its consumption rate, jump frequency, and jump...

Effects of elevated pH on marine copepods in mass cultivation systems

DEFF Research Database (Denmark)

Hansen, Benni Winding; Hansen, Per Juel; Nielsen, Torkel Gissel

2017-01-01

both Acartia spp. and C. typicus had higher mortality at pH 9.5 than at the other pH regimes while E. affinis nauplii were not affected by pH. Wild Acartia spp. and A. tonsa from a culture showed some differences in response although of minor practical importance for aquaculture; both produced no eggs......Female tolerance to pH (8.0–9.5) by six marine copepods, Oithona similis, Temora longicornis, Acartia spp., Centropages typicus, Pseudocalanus elongatus and Eurytemora affinis was investigated to identify robust species for live feed production. The species with the most oceanic...

Algal toxins alter copepod feeding behavior.

Directory of Open Access Journals (Sweden)

Jiarong Hong

Full Text Available Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod's feeding appendages-a "sampling beating" that has short durations (<100 ms and involves little fluid entrainment and a longer duration "grazing beating" that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod's grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod's feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods.

Copepod recruitment and food composition : Do diatoms affect hatching success?

DEFF Research Database (Denmark)

Jonasdottir, Sigrun; Kiørboe, Thomas

1996-01-01

was fed several different diets while egg production and hatching success were monitored. The diet was analysed for fatty acid content as an indicator of food quality. Both egg production and hatching were found to be affected by the nutritional quality of the food. Hatching was also highly dependent......Laboratory experiments were conducted to differentiate between factors controlling the hatching success of copepod eggs. Factors that could affect viability of eggs; viz food quality, female condition and external factors were investigated. In a series of experiments the copepod Acartia tonsa Dana...

Economic feasibility of copepod production for commercial use

DEFF Research Database (Denmark)

Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max

2015-01-01

of producing copepods for commercial application. This is the first empirical study to investigate the economic feasibility of copepod production for commercial use. To this end, a standard cost-benefit analysis based on a prototype production facility of Acartia tonsa (Dana) eggs at Roskilde University...... condition, reduces mal-pigmentation and allows breeding of ‘new’ marine finfish species. However, copepods are not yet commercially produced and therefore not widely used in the aquaculture industry. One of the bottlenecks for large-scale production has been lack of economic knowledge on the feasibility......, Denmark, is employed. The result reveals that commercial production of copepods is economically feasible considering the existing market prices on both copepods and competing live feed items such as rotifers. The study provides valuable information for businesses who consider investing in live feed...

Distribution and mortality of diapause eggs from calanoid copepods in relation to sedimentation regimes

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Hansen, Jørgen L.S.; Andersen, Thorbjørn J.

2011-01-01

Distribution, abundance and age of diapause eggs from three species of calanoid copepods (in particular from Acartia spp. most likely Acartia tonsa, and Centropages hamatus and less numerous from Temora longicornis) were recorded in sediment profiles by enumerating hatched nauplii from incubated...... between the stations. Dating of the sediment cores suggested a ~70-year maximum age of viable eggs on the northernmost stations, and ~28 year at the southernmost stations. The eggs exhibited a significantly higher mortality rate at the southernmost stations compared with the northernmost, 0.35–0.53 year−1...

Bloom-Forming Cyanobacteria Support Copepod Reproduction and Development in the Baltic Sea

Science.gov (United States)

Hogfors, Hedvig; Motwani, Nisha H.; Hajdu, Susanna; El-Shehawy, Rehab; Holmborn, Towe; Vehmaa, Anu; Engström-Öst, Jonna; Brutemark, Andreas; Gorokhova, Elena

2014-01-01

It is commonly accepted that summer cyanobacterial blooms cannot be efficiently utilized by grazers due to low nutritional quality and production of toxins; however the evidence for such effects in situ is often contradictory. Using field and experimental observations on Baltic copepods and bloom-forming diazotrophic filamentous cyanobacteria, we show that cyanobacteria may in fact support zooplankton production during summer. To highlight this side of zooplankton-cyanobacteria interactions, we conducted: (1) a field survey investigating linkages between cyanobacteria, reproduction and growth indices in the copepod Acartia tonsa; (2) an experiment testing relationships between ingestion of the cyanobacterium Nodularia spumigena (measured by molecular diet analysis) and organismal responses (oxidative balance, reproduction and development) in the copepod A. bifilosa; and (3) an analysis of long term (1999–2009) data testing relationships between cyanobacteria and growth indices in nauplii of the copepods, Acartia spp. and Eurytemora affinis, in a coastal area of the northern Baltic proper. In the field survey, N. spumigena had positive effects on copepod egg production and egg viability, effectively increasing their viable egg production. By contrast, Aphanizomenon sp. showed a negative relationship with egg viability yet no significant effect on the viable egg production. In the experiment, ingestion of N. spumigena mixed with green algae Brachiomonas submarina had significant positive effects on copepod oxidative balance, egg viability and development of early nauplial stages, whereas egg production was negatively affected. Finally, the long term data analysis identified cyanobacteria as a significant positive predictor for the nauplial growth in Acartia spp. and E. affinis. Taken together, these results suggest that bloom forming diazotrophic cyanobacteria contribute to feeding and reproduction of zooplankton during summer and create a favorable growth

Bloom-forming cyanobacteria support copepod reproduction and development in the Baltic Sea.

Science.gov (United States)

Hogfors, Hedvig; Motwani, Nisha H; Hajdu, Susanna; El-Shehawy, Rehab; Holmborn, Towe; Vehmaa, Anu; Engström-Öst, Jonna; Brutemark, Andreas; Gorokhova, Elena

2014-01-01

It is commonly accepted that summer cyanobacterial blooms cannot be efficiently utilized by grazers due to low nutritional quality and production of toxins; however the evidence for such effects in situ is often contradictory. Using field and experimental observations on Baltic copepods and bloom-forming diazotrophic filamentous cyanobacteria, we show that cyanobacteria may in fact support zooplankton production during summer. To highlight this side of zooplankton-cyanobacteria interactions, we conducted: (1) a field survey investigating linkages between cyanobacteria, reproduction and growth indices in the copepod Acartia tonsa; (2) an experiment testing relationships between ingestion of the cyanobacterium Nodularia spumigena (measured by molecular diet analysis) and organismal responses (oxidative balance, reproduction and development) in the copepod A. bifilosa; and (3) an analysis of long term (1999-2009) data testing relationships between cyanobacteria and growth indices in nauplii of the copepods, Acartia spp. and Eurytemora affinis, in a coastal area of the northern Baltic proper. In the field survey, N. spumigena had positive effects on copepod egg production and egg viability, effectively increasing their viable egg production. By contrast, Aphanizomenon sp. showed a negative relationship with egg viability yet no significant effect on the viable egg production. In the experiment, ingestion of N. spumigena mixed with green algae Brachiomonas submarina had significant positive effects on copepod oxidative balance, egg viability and development of early nauplial stages, whereas egg production was negatively affected. Finally, the long term data analysis identified cyanobacteria as a significant positive predictor for the nauplial growth in Acartia spp. and E. affinis. Taken together, these results suggest that bloom forming diazotrophic cyanobacteria contribute to feeding and reproduction of zooplankton during summer and create a favorable growth

Ontogenetic development of attack behaviour by turbot larvae when exposed to copepod prey

DEFF Research Database (Denmark)

Højgaard, Jacob K.; Bruno, Eleonora; Støttrup, Josianne Gatt

2018-01-01

offered small nauplii (129–202 μm), large nauplii (222–278 μm) and copepodites (342–542 μm), of the calanoid copepod Acartia tonsa. At 8 DPH, turbot larvae had the highest capture success (67%) when offered small nauplii, with a lower capture success of large nauplii (27%) but totally lacked...... by the larva on the copepod was examined, and the approach pattern of the larva was identified as a controlling mechanism for their strike distance, with the initial approach speed of larva at DPH 10 being significantly less than at DPH 8. In all successful attacks, the strike distance was less than 1.17 mm...

Algal Toxins Alter Copepod Feeding Behavior

Science.gov (United States)

Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A.; Waggett, Rebecca J.; Place, Allen R.

2012-01-01

Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod’s feeding appendages–a “sampling beating” that has short durations (<100 ms) and involves little fluid entrainment and a longer duration “grazing beating” that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod’s grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod’s feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

Glutathione transferase activity and oocyte development in copepods exposed to toxic phytoplankton

DEFF Research Database (Denmark)

Kozlowsky-Suzuki, Betina; Koski, Marja; Hallberg, Eric

2009-01-01

toxins generally observed in copepods. In addition, decreasing gross growth efficiency (GGE) of copepods with increasing concentration of toxic diets could be caused either by a high expenditure coping with toxins (e.g., increase in the activity of detoxification enzymes) or by a deterioration...... of reproductive tissues. To assess the effect of toxic phytoplankton on the activity of detoxification enzymes and on oocyte maturation of Acartia tonsa and Temora longicornis, feeding and egg production experiments were carried out with a variety of toxic diets and an adequate non-toxic food control (Rhodomonas...... spp.) all provided as single species diets. Toxic diets included the nodularin-producing cyanobacterium Nodularia spumigena, the dinoflagellates Alexandrium minutum, and A. tamarense, which contained Paralytic Shellfish Poisoning (PSP) toxins, the dinoflagellate Prorocentrum lima with Diarrhetic...

Biological processes in the North Sea: vertical distribution and reproduction of neritic copepods in relation to environmental factors

DEFF Research Database (Denmark)

Koski, Marja; Jonasdottir, Sigrun; Bagøien, Espen

2011-01-01

for reproduction compared with surface waters and (iii) if the secondary production is thus higher in the frontal areas with a subsurface chlorophyll maximum. In addition, we wanted to (iv) identify the most important environmental factors determining the reproduction of neritic copepods in the North Sea. We......We studied the vertical distribution and reproduction of dominant neritic copepod species in the Dogger Bank area and surrounding North Sea to reveal (i) if these species are concentrated in the subsurface chlorophyll maximum layer, (ii) if the chlorophyll maximum offers superior food conditions...... observed a higher egg production of cultured Acartia tonsa when fed with the seston from chlorophyll maximum, but no evidence of a higher copepod abundance in this layer. Secondary production was highest at the station closest to the upwelling of new nutrients, although seasonal differences...

Rapid adaptation to oil exposure in the cosmopolitan copepod Acartia tonsa

DEFF Research Database (Denmark)

Krause, K. E.; Dinh, Khuong Van; Nielsen, Torkel Gissel

Oil spills are potential environmental hazards to marine ecosystems worldwide. Oil spills may persist in seawater longer than one generation of many zooplankton species. However, whether populations of short-lived and fast growing marine organisms adapt to oil exposure through natural selection...... in size at maturity of females was less pronounced in the second generation. Strikingly, both survival, egg production and hatching success were recovered in the second generation, indicating a rapid selection towards individuals with adaptations to deal with pyrene exposure. Our results show...... that populations of short-lived and fast-growing copepods have the potential of showing surprisingly strong resilience to the type of oil contamination they might face in their natural coastal habitats...

Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System.

Science.gov (United States)

Skovgaard, Alf; Castro-Mejia, Josue Leonardo; Hansen, Lars Hestbjerg; Nielsen, Dennis Sandris

2015-01-01

Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes.

Host-Specific and pH-Dependent Microbiomes of Copepods in an Extensive Rearing System.

Directory of Open Access Journals (Sweden)

Alf Skovgaard

Full Text Available Copepods are to an increasing extent cultivated as feed for mariculture fish larvae with variable production success. In the temperate climate zone, this production faces seasonal limitation due to changing abiotic factors, in particular temperature and light. Furthermore, the production of copepods may be influenced by biotic factors of the culture systems, such as competing microorganisms, harmful algae, or other eukaryotes and prokaryotes that may be non-beneficial for the copepods. In this study, the composition of bacteria associated with copepods was investigated in an extensive outdoor copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE analysis, a clear difference was found between the microbiomes of the two copepod species, Acartia tonsa and Centropages hamatus, present in the system. This pattern was corroborated through 454/FLX-based 16S rRNA gene amplicon sequencing of copepod microbiomes, which furthermore showed that the abiotic parameters pH and oxygen concentration in rearing tank water were the key factors influencing composition of copepod microbiomes.

Temperature effects on copepod egg hatching: does acclimatization matter?

DEFF Research Database (Denmark)

Hansen, Benni Winding; Drillet, Guillaume; Kozmér, A.

2010-01-01

This report investigates female sizes, egg sizes and egg hatching rates in relation to temperature for the near-shore calanoid copepod Acartia tonsa cultured at 6, 9, 14 and 24°C for several generations to achieve acclimatization. Inverse size relationships of eggs and females were revealed...... with increasing temperature. Eggs produced at 6°C were 85 ± 4 µm in diameter, but decreased to 80 ± 3 µm at 24°C. Female cephalothorax length was 840 ± 52 and 692 ± 39 µm at 9 and 24°C, respectively. Parallel hatching experiments were performed between non-acclimatized and acclimatized cultures across a range...... of temperatures reflecting natural conditions in Danish waters. A greater fraction of eggs enter quiescence as temperature declines. Eggs were able to hatch at temperatures as low as 1.5°C. Final egg hatching success increased with temperature. Acclimatization of the copepods resulted in a lower maximum hatching...

Relationships between copepod community structure, rainfall regimes, and hydrological variables in a tropical mangrove estuary (Amazon coast, Brazil)

Science.gov (United States)

Magalhães, André; Pereira, Luci Cajueiro Carneiro; da Costa, Rauquírio Marinho

2015-03-01

The influence of rainfall and hydrological variables on the abundance and diversity of the copepod community was investigated on a monthly basis over an annual cycle in the Taperaçu mangrove estuary. In general, the results show that there were no clear spatial or tidal patterns in any biological variables during the study period, which was related to the reduced horizontal gradient in abiotic parameters, determined mainly by the morphological and morphodynamic features of the estuary. Nevertheless, seasonal and monthly trends were recorded in both the hydrological data and the abundance of the dominant copepod species. In particular, Pseudodiaptomus marshi (6,004.6 ± 22,231.6 ind m-3; F = 5.0, p < 0.05) and Acartia tonsa (905.6 ± 2,400.9 ind m-3; F = 14.6, p < 0.001) predominated during the rainy season, whereas Acartia lilljeborgii (750.8 ± 808.3 ind m-3; U = 413.0, p < 0.01) was the most abundant species in the dry season. A distinct process of succession was observed in the relative abundance of these species, driven by the shift in the rainfall regime, which affected hydrological, in particular salinity, and consequently the abundance of copepod species. We suggest that this may be a general pattern governing the dynamics of copepod populations in the estuaries of the Brazilian Amazonian region.

Dealing with the presence of the ciliate Euplotes sp. in cultures of the copepod Acartia tonsa

DEFF Research Database (Denmark)

Drillet, Guillaume; Dutz, Jörg

2014-01-01

Ciliates in live feed cultures can be a pest that lower production yields. This could dramatically affect the management and success of copepod cultures. In this study, we investigated the effect of the ciliate Euplotes sp. on egg production, specific egg production and egg hatching success...... of unsaturated fatty acids, but the amount of fatty acids compared to their carbon weight was very low and, therefore, it was considered as a poor food source. We propose a short-term interruption of food supply to copepod cultures in order to mitigate bloom formation of ciliates. This will force copepods...

A comprehensive and precise quantification of the calanoid copepod Acartia tonsa (Dana) for intensive live feed cultures using an automated ZooImage system

DEFF Research Database (Denmark)

Vu, Minh Thi Thuy; Jepsen, Per Meyer; Hansen, Benni Winding

2014-01-01

culturing parameters in intensive A. tonsa culture such as hatching success, mortality rate, development rate, and reproduction output of A. tonsa can be calculated automatically. Moreover, ZooImage is set up with an inexpensive desktop scanner and computer that can easily be applied in aquaculture...

Dissolution of coccolithophorid calcite by microzooplankton and copepod grazing

Science.gov (United States)

Antia, A. N.; Suffrian, K.; Holste, L.; Müller, M. N.; Nejstgaard, J. C.; Simonelli, P.; Carotenuto, Y.; Putzeys, S.

2008-01-01

Independent of the ongoing acidification of surface seawater, the majority of the calcium carbonate produced in the pelagial is dissolved by natural processes above the lysocline. We investigate to what extent grazing and passage of coccolithophorids through the guts of copepods and the food vacuoles of microzooplankton contribute to calcite dissolution. In laboratory experiments where the coccolithophorid Emiliania huxleyi was fed to the rotifer Brachionus plicatilis, the heterotrophic flagellate Oxyrrhis marina and the copepod Acartia tonsa, calcite dissolution rates of 45-55%, 37-53% and 5-22% of ingested calcite were found. We ascribe higher loss rates in microzooplankton food vacuoles as compared to copepod guts to the strongly acidic digestion and the individual packaging of algal cells. In further experiments, specific rates of calcification and calcite dissolution were also measured in natural populations during the PeECE III mesocosm study under differing ambient pCO2 concentrations. Microzooplankton grazing accounted for between 27 and 70% of the dynamic calcite stock being lost per day, with no measurable effect of CO2 treatment. These measured calcite dissolution rates indicate that dissolution of calcite in the guts of microzooplankton and copepods can account for the calcite losses calculated for the global ocean using budget and model estimates.

The kinematics of swimming and relocation jumps in copepod nauplii

DEFF Research Database (Denmark)

Borg, Marc Andersen; Bruno, Eleonora; Kiørboe, Thomas

2012-01-01

Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and cop......Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella...... of pelagic copepods: Temora longicornis, Oithona davisae and Acartia tonsa. The kinematics of jumping is similar between the three species. Jumps result in a very erratic translation with no phase of passive coasting and the nauplii move backwards during recovery strokes. This is due to poorly synchronized...... recovery strokes and a low beat frequency relative to the coasting time scale. For the same reason, the propulsion efficiency of the nauplii is low. Given the universality of the nauplius body plan, it is surprising that they seem to be inefficient when jumping, which is different from the very efficient...

Motility of copepod nauplii and implications for food encounter

DEFF Research Database (Denmark)

Titelman, Josefin; Kiørboe, Thomas

2003-01-01

(Centropages typicus, Calanus helgolandicus, Temora longicornis, Acartia tonsa, Eurytemora affinis and Euterpina acutifrons). Behaviors of individual nauphi were divided into sequences of sinking, swimming and jumping events. Motility behavior is both stage- and species-specific in terms of appearance......Velocity differences drive all encounter processes. Therefore, knowledge of both prey and predator motility are essential in order to understand feeding behavior and predict food acquisition rates. Here, we describe and quantify the motility behavior of young and old naupliar stages of 6 copepods...... of tracks, speeds, durations and frequencies of events as well as time budgets. Motility mode often changes drastically during naupliar ontogeny. Crudely, nauplii can be divided into those moving with a jump-sink type of motility of various frequencies (1 min(-1) to 3 s(-1)) and those swimming...

Copepod community structure in Bahia de Banderas during the 2008-2009 La Niña and their transition to the 2009-2010 El Niño

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Jiménez-Pérez, L.C.

2016-09-01

Full Text Available In order to investigate the taxonomic copepod community structure and its relations with the climate conditions in the Pacific Ocean, bimonthly samples were made between February 2009 and April 2010. Samples were collected by vertical tows between the surface and the vicinity of the bottom with a 40 cm mouth diameter and 335 µ mesh size standard zooplankton net. At the beginning of the study water temperatures were low indicating that La Niña conditions prevailed in the bay. However, at the end of June, 2 °C warmer waters associated with El Niño 2009-2010 arrival were detected. These conditions persisted at least until February 2010, and by April water temperature returned to normal. 57 copepods species were recorded, being Acartia tonsa, Acartia lilljeborgi, Oithona plumífera, Centropages furcatus and Nannocalanus minor the most representative species. These five populations accounted most of the 90 % of the collected animals. Cluster and Non-Metric Multidimensional Scaling (NMDS methods show two groups that seem to be associated with La Niña and El Niño conditions. The analysis of similarities (ANOSIM indicated that these assemblages were different (r=0.411; p=0.01 %. Simper analysis indicated that A. tonsa was the dominant population (85.4 % at the end of the 2008-2009 La Niña; this population was followed by A. lilljeborgi (7.9 % and Pareucalanus subtenuis (2.5 %. During the El Niño the dominance of A. tonsa disappeared (32 % while Oithona plumífera, Temora discaudata and Undinula darwinii increased. At the end of El Niño, species diversity and richness also changed. At the end of the 2008-2009 La Niña conditions, 40 species were recorded, while during El Niño the species richness increased to 52 species.

The occurrence of Acartia species and their environmental characteristics at three ports in Korea

Science.gov (United States)

Kang, Jung-Hoon

2011-12-01

This study investigated the occurrence of Acartia copepods and their environmental characteristics to identify the existence and survival of foreign species at domestic ports in Korea. Copepods samples were collected seasonally, and temperature, salinity, dissolved oxygen (DO), total suspended solids (TSS), and chlorophyll- a (chl- a) were measured at the seaports Incheon, Gwangyang, and Ulsan from 2007 to 2009. No foreign species was found and all of the Acartia copepods observed had been recorded in Korean waters previously. Acartia omorii, A. hongi, and A. pacifica were found at all three seaports, whereas portspecific species were found at Incheon ( A. sinjiensis) and Ulsan ( A. steueri, A. negligens, and A. danae). When chl- a and DO were not limited, eurythermal and euryhaline A. hongi, A. omorii, and A. hudsonica occurred at TSS concentrations between 38 and 183 mg·L-1, while warm-water copepods ( A. pacifica, A. ohtsukai, A. sinjiensis, and A. erythraea) occurred at TSS concentrations food was not limiting. These results indicated that the occurrence of Acartia copepods and related environmental characteristics are crucial information for differentiating foreign species from the native community and predicting the potential for foreign copepods to become established after their introduction to a seaport.

Crypthecodinium cohnii: a promising prey toward large-scale intensive rearing of the live feed copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Jakobsen, H. H.; Thoisen, C.; Hansen, B. W.

2018-01-01

. The trade-off of switching to the heterotrophic dinoflagellate diet is that the copepod performance is about 40% lower. Still, we propose that eliminating light in the rearing of copepod feed makes C. cohnii an interesting alternative and an economical feasible feed worth pursuing in large-scale rearing...

Recent advances within intensive Recirculated Aquaculture System cultivation of the calanoid copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Jepsen, Per Meyer; Højgaard, Jacob Kring; Drillet, Guillaume

2014-01-01

) was constructed as a part of the IMPAQ project “IMProvement of AQuaculture high quality fish fry production”. We present recent advance within RAS culture for copepods, and lesson learned from rearing the specie. Further we present physical and biological culture restrictions in terms of water quality (NH3...

Effects of high CO2 seawater on the copepod (Acartia tsuensis) through all life stages and subsequent generations

International Nuclear Information System (INIS)

Kurihara, Haruko; Ishimatsu, Atsushi

2008-01-01

We studied the effects of exposure to seawater equilibrated with CO 2 -enriched air (CO 2 2380 ppm) from eggs to maturity and over two subsequent generations on the copepod Acartia tsuensis. Compared to the control (CO 2 380 ppm), high CO 2 exposure through all life stages of the 1st generation copepods did not significantly affect survival, body size or developmental speed. Egg production and hatching rates were also not significantly different between the initial generation of females exposed to high CO 2 and the 1st and 2nd generation females developed from eggs to maturity in high CO 2 . Thus, the copepods appear more tolerant to increased CO 2 than other marine organisms previously investigated for CO 2 tolerance (i.e., sea urchins and bivalves). However, the crucial importance of copepods in marine ecosystems requires thorough evaluation of the overall impacts of marine environmental changes predicted to occur with increased CO 2 concentrations, i.e., increased temperature, enhanced UV irradiation, and changes in the community structure and nutritional value of phytoplankton

Patterns of copepod diversity in the Chilean coastal upwelling system

Science.gov (United States)

Hidalgo, Pamela; Escribano, Ruben; Vergara, Odette; Jorquera, Erika; Donoso, Katty; Mendoza, Paula

2010-12-01

The copepod community structure from the Northern and Central/southern upwelling regions off Chile was studied and compared. The derived community descriptors were species abundance (N), species richness (R) and the Shannon-Wiener diversity index (H'). These descriptors were related to distinct habitats and conditions, sea surface temperature (SST) and depth of the upper boundary of the oxygen minimum zone (OMZ). From 159 samples, obtained between 2002 and 2008, a total number of 118 species were found of which the calanoids Paracalanus indicus, Acartia tonsa and Eucalanus inermis, along with the cyclopoid Oithona similis, and the poecilostomatoids Triconia conifera and Oncaea media were the dominant species. H' was higher in the northern region, but no differences in N and R were detected between regions. N was higher in the epipelagic vs the deep habitat, but R and H' did not differ. N, R and H' correlated positively to SST and negatively to OMZ depth. The ascent of the OMZ to the upper layer forced by upwelling was proposed as a mechanism that aggregates and increases copepod diversity in the food-rich photic zone. All these findings suggest a fundamental role of upwelling variation for modulating copepod dynamics and community structure in this highly productive but strongly variable marine ecosystem.

Calcium Carbonate Dissolution Above the Lysocline: Implications of Copepod Grazing on Coccolithophores

Science.gov (United States)

White, M. M.; Waller, J. D.; Lubelczyk, L.; Drapeau, D.; Bowler, B.; Wyeth, A.; Fields, D.; Balch, W. M.

2016-02-01

Copepod-coccolithophore predator-prey interactions are of great importance because they facilitate the export of particulate inorganic and organic carbon (PIC and POC) from the surface ocean. Coccolith dissolution in acidic copepod guts has been proposed as a possible explanation for the paradox of PIC dissolution above the lysocline, but warrants further investigation. Using a new application of the 14C-microdiffusion technique, we investigated the dissolution of coccoliths in copepod guts. We considered both an estuarine predator-prey model (Acartia tonsa and Pleurochrysis carterae) and an open ocean predator-prey model (Calanus finmarchicus and Emiliania huxleyi). Additionally, we considered the impacts of pCO2 on this process to advance our understanding of the effects of ocean acidification on trophic interactions. In the estuarine predator-prey model, fecal pellets produced immediately after previously-starved copepods grazed on P. carterae had PIC/POC ratios 27-40 % lower than that of the algae, indicating PIC dissolution within the copepod gut, with no impact of pCO2 on this dissolution. Subsequent fecal pellets showed increasing PIC/POC, suggesting that calcite dissolution decreases as the gut fills. The open ocean predator-prey model showed equivocal results, indicating high variability among individual grazing behavior, and therefore no consistent impact of copepod grazing on coccolith dissolution above the lysocline in the open ocean. We will further discuss the effects of fecal pellet PIC/POC ratios on sinking rate.

Predation by the Dwarf Seahorse on Copepods: Quantifying Motion and Flows Using 3D High Speed Digital Holographic Cinematography - When Seahorses Attack!

Science.gov (United States)

Gemmell, Brad; Sheng, Jian; Buskey, Ed

2008-11-01

Copepods are an important planktonic food source for most of the world's fish species. This high predation pressure has led copepods to evolve an extremely effective escape response, with reaction times to hydrodynamic disturbances of less than 4 ms and escape speeds of over 500 body lengths per second. Using 3D high speed digital holographic cinematography (up to 2000 frames per second) we elucidate the role of entrainment flow fields generated by a natural visual predator, the dwarf seahorse (Hippocampus zosterae) during attacks on its prey, Acartia tonsa. Using phytoplankton as a tracer, we recorded and reconstructed 3D flow fields around the head of the seahorse and its prey during both successful and unsuccessful attacks to better understand how some attacks lead to capture with little or no detection from the copepod while others result in failed attacks. Attacks start with a slow approach to minimize the hydro-mechanical disturbance which is used by copepods to detect the approach of a potential predator. Successful attacks result in the seahorse using its pipette-like mouth to create suction faster than the copepod's response latency. As these characteristic scales of entrainment increase, a successful escape becomes more likely.

Interactions between populations of the calanoid copepod Acartia tonsa Dana and the harpacticoid copepod Tisbe holothuriae Humes in mixed cultures of live feed for fish larvae

DEFF Research Database (Denmark)

Hansen, Benni Winding; Boesen, Emil; Brodnicke, Ole Bjørn

2018-01-01

by the R setup compared with S setup. A long-term solution to limit the presence of T. holothuriae is to apply turbulence level in a classical stagnant tank setup to an extend that suppress T. holothuriae and simultaneously allow algae in suspension as food for A. tonsa, make their eggs sediment as well...

Prey detection and prey capture in copepod nauplii.

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Eleonora Bruno

Full Text Available Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds numbers due to the thick viscous boundary layer surrounding the attacking nauplius. We use high-speed video to describe the detection and capture of phytoplankton prey by the nauplii of two ambush feeding species (Acartia tonsa and Oithona davisae and by the nauplii of one feeding-current feeding species (Temora longicornis. We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding current that pulls in the prey from behind towards the mouth. The feeding-current feeding nauplius detects prey arriving in the feeding current but only when the prey is intercepted by the setae on the feeding appendages. This elicits an altered motion pattern of the feeding appendages that draws in the prey.

Effects of high CO{sub 2} seawater on the copepod (Acartia tsuensis) through all life stages and subsequent generations

Energy Technology Data Exchange (ETDEWEB)

Kurihara, Haruko [Institute for East China Sea Research, Nagasaki University, 1551-7 Tairamachi, Nagasaki 851-2213 (Japan)], E-mail: harukoku@e-mail.jp; Ishimatsu, Atsushi [Institute for East China Sea Research, Nagasaki University, 1551-7 Tairamachi, Nagasaki 851-2213 (Japan)

2008-06-15

We studied the effects of exposure to seawater equilibrated with CO{sub 2}-enriched air (CO{sub 2} 2380 ppm) from eggs to maturity and over two subsequent generations on the copepod Acartia tsuensis. Compared to the control (CO{sub 2} 380 ppm), high CO{sub 2} exposure through all life stages of the 1st generation copepods did not significantly affect survival, body size or developmental speed. Egg production and hatching rates were also not significantly different between the initial generation of females exposed to high CO{sub 2} and the 1st and 2nd generation females developed from eggs to maturity in high CO{sub 2}. Thus, the copepods appear more tolerant to increased CO{sub 2} than other marine organisms previously investigated for CO{sub 2} tolerance (i.e., sea urchins and bivalves). However, the crucial importance of copepods in marine ecosystems requires thorough evaluation of the overall impacts of marine environmental changes predicted to occur with increased CO{sub 2} concentrations, i.e., increased temperature, enhanced UV irradiation, and changes in the community structure and nutritional value of phytoplankton.

Towards an internationally harmonized test method for reproductive and developmental effects of endocrine disrupters in marine copepods

DEFF Research Database (Denmark)

Kusk, Kresten Ole; Wollenberger, Leah

2007-01-01

with marine copepods (Acartia tonsa, Nitocra spinipes, Tisbe battagliai, and Amphiascus tenuiremis). The present paper gives an overview on the endocrine system of crustaceans with special emphasis on development and reproduction, which are targets for endocrine disruption, and reviews available methods......New and updated methods to detect and characterize endocrine disrupting chemicals (EDCs) are urgently needed for the purpose of environmental risk assessment since these substances are often not detected using existing chronic toxicity tests. Numerous reports on the effects of EDCs on crustacean...... development and reproduction have been published and the development of life-cycle tests with crustaceans has been prioritized within the OECD work program for endocrine disrupter testing and assessment. As a result, Sweden, and Denmark initiated a proposal for development of a full life-cycle test...

Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon

DEFF Research Database (Denmark)

Picone, Marco; Bergamin, Martina; Delaney, Eugenia

2018-01-01

between samples and control) and to investigate the possible correlation with sediment chemistry and physical properties. The results showed that statistical performances of the LDR test with A. tonsa correspond with the outcomes of other tests applied to the sediment-water interface (Strongylocentrotus...

Swimming and escape behavior of copepod nauplii: implications for predator-prey interactions among copepods

DEFF Research Database (Denmark)

Titelman, Josefin

2001-01-01

This study focuses on how prey behavior may affect predation risk through encounter rates and the escape success of the prey given an encounter. Temora longicornis nauplii require stronger hydrodynamic signals to elicit escape than Acartia tonsa nauplii (critical fluid deformation rates, Delta......* of 2.8 to 4.0 and 1.2 to 2.5 s(-1), respectively) suggesting that T. longicornis may be more susceptible to predation. Quantification of naupliar motility behavior and subsequent estimation of the hydrodynamic signals which the nauplii generate suggest that an adult female Centropages typicus may......, the behavior of A. tonsa acts predominantly at the post-encounter stage where its sensitivity to hydrodynamic signals (i,e., low Delta*) effectively compensates for the high predator encounter rate generated by its motility....

Effect of ocean acidification on the nutritional quality of phytoplankton for copepod reproduction

Science.gov (United States)

Meyers, M.; Cochlan, W. P.; Kimmerer, W.; Carpenter, E. J.

2016-02-01

Phytoplankton are the oceans' primary producers of essential polyunsaturated fatty acids (PUFA), which provide marine organisms with nutrients needed for health and reproduction. It is hypothesized that future ocean acidification (OA) conditions could change the availability of phytoplankton PUFAs for ecologically significant predators such as copepods, affecting their reproductive success. Three species of phytoplankton (Rhodomonas salina, Skeletonema marinoi, Prorocentrum micans) were cultured under present-day (400ppm CO2, pH 8.1) and predicted future (1000ppm CO2, pH 7.8) oceanic conditions. For four days, female Acartia tonsa copepods were fed a phytoplankton mixture from either the present-day or predicted-future treatment. To assess changes in phytoplankton PUFA content, fatty acid profiles were analyzed via capillary gas chromatography. Copepod egg production (EP), hatching success (HS), and egg viability (EV) were determined to assess copepod reproductive success. Fatty acid analysis shows essential PUFAs comprise a smaller percentage of total fatty acids in phytoplankton cultured under high pCO2 (Rho 21.5%; Ske 14.1%; Pro 14.4%) compared to those cultured under present-day pCO2 (Rho 28.8%, Ske 32.7%, Pro 39.3%). Copepod reproduction data demonstrate that females fed phytoplankton cultured under high pCO2 have significantly lower EP (μ=14.3 eggs female-1), HS (μ=35.8%), and EV (μ=12.5%) compared to reproductive success of females fed phytoplankton cultured under present-day CO2 (EP μ=27.0 eggs female-1; HS μ=91.5%; EV μ=96.6%). This study demonstrates that OA can change the nutritional quality of primary producers, which can affect the reproductive success of fundamental secondary consumers.

Influence of UVB radiation on the lethal and sublethal toxicity of dispersed crude oil to planktonic copepod nauplii.

Science.gov (United States)

Almeda, Rodrigo; Harvey, Tracy E; Connelly, Tara L; Baca, Sarah; Buskey, Edward J

2016-06-01

Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia tonsa, Temora turbinata and Pseudodiaptomus pelagicus. Low concentrations of dispersed crude oil (1 μL L(-1)) caused a significant reduction in survival, growth and swimming activity of copepod nauplii after 48 h of exposure. UVB radiation increased toxicity of dispersed crude oil by 1.3-3.8 times, depending on the experiment and measured variables. Ingestion of crude oil droplets may increase photoenhanced toxicity of crude oil to copepod nauplii by enhancing photosensitization. Photoenhanced sublethal toxicity was significantly higher when T. turbinata nauplii were exposed to dispersant-treated oil than crude oil alone, suggesting that chemical dispersion of crude oil may promote photoenhanced toxicity to marine zooplankton. Our results demonstrate that acute exposure to concentrations of dispersed crude oil and dispersant (Corexit 9500) commonly found in the sea after oil spills are highly toxic to copepod nauplii and that natural levels of UVB radiation substantially increase the toxicity of crude oil to these planktonic organisms. Overall, this study emphasizes the importance of considering sunlight in petroleum toxicological studies and models to better estimate the impact of crude oil spills on marine zooplankton. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A new large egg type from the marine live feed calanoid copepod Acartia tonsa (Dana)-Perspectives for selective breeding of designer feed for hatcheries

DEFF Research Database (Denmark)

Hammervold, Stian Halsen; Glud, Ronnie N.; Evjemo, Jan Ove

2015-01-01

correspondingly large, and the copepods remained large when developing into adulthood. The fact that copepods hatched from large eggs were fertile indicates no chromosomal abnormalities and suggests that this egg type represents the upper tail end of eggs in a classical normal distribution of size vs. frequency...

Ecology and Distribution of Copepods from the Salt Pan Ecosystems of Mumbai, West Coast of India

Digital Repository Service at National Institute of Oceanography (India)

Stephen, R.; Jayalakshmy, K.V.; NaveenKumar, K.R.; Nair, V.R.

Ecology, distribution and diversity of Copepod collected from two salt pans of Mumbai, India, are presented. Copepods, the mai zooplankton components, consisted mainly of Bestiolina similis, Acartia southwelli, Oithona sp., O. similis, O. hebes...

Effect of advection on variations in zooplankton at a single location near Cabo Nazca, Peru

Energy Technology Data Exchange (ETDEWEB)

Smith, S L; Brink, K H; Santander, H; Cowles, T J; Huyer, A

1980-04-01

Temporal variations in the biomass and species composition of zooplankton at a single midshelf station in an upwelling area off Peru can be explained to a large extent by onshore-offshore advection in the upper 20 m of the water column. During periods of strong or sustained near-surface onshore flow, peaks in biomass of zooplankton were observed at midshelf and typically oceanic species of copepod were collected. In periods of offshore flow at the surface, a copepod capable of migrating into oxygen-depleted layers deeper than 30 m was collected. A simple translocation model of advection applied to the cross-shelf distribution of Paracalanus parvus suggests that the fluctuations in P. pavus observed in the midshelf time-series were closely related to onshore-offshore flow in the upper 20 m. Fluctuations in abundance of the numerically dominant copepod, Acartia tonsa, were apparently affected by near surface flow also. The population age-structure suggests that A. tonsa was growing at maximal rates, due in part to its positive feeding response to the dinoflagellate/diatom assemblage of phytoplankton.

Seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep – numerical simulations

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L. Dzierzbicka-Głowacka

2006-01-01

Full Text Available A population dynamics model for copepods is presented, describing the seasonal dynamics of Pseudocalanus minutus elongatus and Acartia spp. in the southern Baltic Sea (Gdańsk Deep. The copepod model was coupled with a one-dimensional physical and biological upper layer model for nutrients (total inorganic nitrogen, phosphate, phytoplankton, microzooplankton, and an early juvenile of herring as a predator. In this model, mesozooplankton (herbivorous copepods has been introduced as an animal having definite patterns of growth in successive stages, reproduction and mortality. The populations are represented by 6 cohorts in different developmental stages, thus assuming that recruitment of the next generation occurs after a fixed period of adult life. The copepod model links trophic processes and population dynamics, and simulates individual growth within cohorts and the changes in biomass between cohorts. The simulations of annual cycles of copepods contain one complete generation of Pseudocalanus and two generations of Acartia in the whole column water, and indicate the importance of growth in the older stages of 6 cohorts of each species, to arrive at a total population biomass. The peaks of copepods' biomass are larger at the turn of June and July for Pseudocalanus and smaller in July for Acartia, lagging that of phytoplankton by ca. two mouths, due to the growth of cohorts in successive stages and egg production by females. The numerical results show that the investigated species could not be the main factor limiting the spring phytoplankton bloom in the Gdańsk Deep, because the initial development was slow for Acartia and faster for Pseudocalanus, but the main development formed after the bloom, in both cases. The phytoplankton bloom is very important in the diet of the adults of the copepods, but it is not particularly important for the youngest part of new generation (early nauplii. However, the simulated microzooplankton biomass was

Impact of a power plant cooling system on copepod and meroplankton survival (Bahía Blanca estuary, Argentina Impacto del sistema de enfriamiento de una central termoeléctrica sobre la supervivencia de copépodos y meroplancton (estuario de Bahía Blanca, Argentina

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Mónica Susana Hoffmeyer

2005-09-01

Full Text Available The impact of a power plant cooling system in the Bahía Blanca estuary (Argentina on the survival of target zooplanktonic organisms (copepods and crustacean larvae and on overall mesozooplankton abundance was evaluated over time. Mortality rates were calculated for juveniles and adults of four key species in the estuary: Acartia tonsa Dana, 1849 and Eurytemora americana Williams, 1906 (native and invading copepods, and larvae of the crab Chasmagnathus granulata Dana, 1851 and the invading cirriped Balanus glandula Darwin, 1854. Mean total mortality values were up to four times higher at the water discharge site than at intake, though for all four species, significant differences were only registered in post-capture mortality. The findings show no evidence of greater larval sensitivity. As expected, the sharpest decrease in overall mesozooplankton abundance was found in areas close to heated water discharge.El impacto del sistema de enfriamiento de una planta termoeléctrica ubicada en el estuario de Bahía Blanca, Argentina, fue evaluado en el tiempo, sobre la supervivencia de especies zooplanctónicas seleccionadas (copépodos y larvas de crustáceos y la abundancia general del meso-zooplancton. Se calcularon tasas de mortalidad de juveniles y adultos de cuatro especies clave en el estuario: Acartia tonsa Dana,1849 y Eurytemora americana Williams,1906 (copépodos nativo e invasor, y larvas del cangrejo Chasmagnathus granulata Dana, 1851 y del cirripedio invasor Balanus glandula Darwin, 1854. Los valores medios hallados de la tasa de mortalidad total, fueron hasta cuatro veces más altos en la descarga que en el agua de entrada al sistema. Sin embargo sólo se registraron diferencias significativas entre estos dos sitios, en los valores de mortalidad post-captura obtenidos para las cuatro especies. Los resultados del estudio no demostraron una mayor sensibilidad larval. Como se esperaba, la disminución más pronunciada en la abundancia general

Feeding and growth of larval herring,Clupea harengus, in relation to density of copepod nauplii

DEFF Research Database (Denmark)

Kiørboe, Thomas; Munk, Peter

1986-01-01

Feeding and growth rates of 1–3 wk old herring larvae from four different stocks were compared in laboratory experiments (8°C). For most of the larval groups, feeding rate was saturated at nauplii (Acartia tonsa, nauplii stages 3–5) densities over 301−1 (5 μg d.w. 1−1). Specific growth rate incre...

Marine microalgae attack and feed on metazoans

DEFF Research Database (Denmark)

Berge, Terje; Poulsen, Louise K.; Moldrup, Morten

2012-01-01

Free-living microalgae from the dinoflagellate genus Karlodinium are known to formmassive blooms in eutrophic coastal waters worldwide and are often associated with fish kills. Natural bloom populations, recently shown to consist of the two mixotrophic and toxic species Karlodinium armiger...... and Karlodinium veneficum have caused fast paralysis and mortality of finfish and copepods in the laboratory, and have been associated with reduced metazooplankton biomass in-situ. Here we show that a strain of K. armiger (K-0688) immobilises the common marine copepod Acartia tonsa in a densitydependent manner...... and collectively ingests the grazer to promote its own growth rate. In contrast, four strains of K. veneficum did not attack or affect the motility and survival of the copepods. Copepod immobilisation by the K. armiger strain was fast (within 15min) and caused by attacks of swarming cells, likely through...

The importance of uptake from food for the bioaccumulation of PCB and PBDE in the marine planktonic copepod Acartia clausi

Energy Technology Data Exchange (ETDEWEB)

Magnusson, Kerstin, E-mail: kerstin.magnusson@marecol.gu.se [Department of Marine Ecology-Kristineberg, University of Gothenburg, Kristineberg 566, SE 45034 Fiskebaeckskil (Sweden); Tiselius, Peter [Department of Marine Ecology-Kristineberg, University of Gothenburg, Kristineberg 566, SE 45034 Fiskebaeckskil (Sweden)

2010-07-15

The accumulation of {sup 14}C-labelled PCB 31, PCB 101, PCB 153 and PBDE 99 was investigated at the two lowest trophic levels of the pelagic food web. Accumulation was measured in the small phytoplankter Thalassiosira weissflogii (Coscinodiscophyceae: Thalassiosirales) and in the neritic zooplankter Acartia clausi (Copepoda: Calanoida) exposed to the substance either only via water or through ingestion of contaminated T. weissflogii. Bioaccumulation factors (BAFs) for all four compounds were significantly higher in A. clausi feeding on contaminated phytoplankton than in animals exposed only via water. The log BAF for the PCBs increased linearly with the octanol-water partitioning coefficients (log K{sub OW}) in both the algae and the copepods, but with steeper slopes for feeding than non-feeding animals. Reported values for K{sub OW} for PBDEs vary by almost an order of magnitude and it was therefore not meaningful to calculate a log BAF - log K{sub OW} ratio for PBDE 99. It is clear that the nutritional status of the zooplankton affects the uptake of the compounds and that the bioaccumulation cannot be modelled as a passive partitioning between the organisms and the surrounding water. Small copepods are typical of coastal waters and point sources (both temporal and spatial) may be the rule for HOC releases into the sea. Thus, the pathways shown in this study are important and realistic.

The importance of uptake from food for the bioaccumulation of PCB and PBDE in the marine planktonic copepod Acartia clausi

International Nuclear Information System (INIS)

Magnusson, Kerstin; Tiselius, Peter

2010-01-01

The accumulation of 14 C-labelled PCB 31, PCB 101, PCB 153 and PBDE 99 was investigated at the two lowest trophic levels of the pelagic food web. Accumulation was measured in the small phytoplankter Thalassiosira weissflogii (Coscinodiscophyceae: Thalassiosirales) and in the neritic zooplankter Acartia clausi (Copepoda: Calanoida) exposed to the substance either only via water or through ingestion of contaminated T. weissflogii. Bioaccumulation factors (BAFs) for all four compounds were significantly higher in A. clausi feeding on contaminated phytoplankton than in animals exposed only via water. The log BAF for the PCBs increased linearly with the octanol-water partitioning coefficients (log K OW ) in both the algae and the copepods, but with steeper slopes for feeding than non-feeding animals. Reported values for K OW for PBDEs vary by almost an order of magnitude and it was therefore not meaningful to calculate a log BAF - log K OW ratio for PBDE 99. It is clear that the nutritional status of the zooplankton affects the uptake of the compounds and that the bioaccumulation cannot be modelled as a passive partitioning between the organisms and the surrounding water. Small copepods are typical of coastal waters and point sources (both temporal and spatial) may be the rule for HOC releases into the sea. Thus, the pathways shown in this study are important and realistic.

Ocean acidification challenges copepod phenotypic plasticity

Science.gov (United States)

Vehmaa, Anu; Almén, Anna-Karin; Brutemark, Andreas; Paul, Allanah; Riebesell, Ulf; Furuhagen, Sara; Engström-Öst, Jonna

2016-11-01

Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ˜ 365-1231 µatm) and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm) or quality (C : N) weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods

International Nuclear Information System (INIS)

Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

2016-01-01

We investigated and quantified defecation rates of crude oil by 3 species of marine planktonic copepods (Temora turbinata, Acartia tonsa, and Parvocalanus crassirostris) and a natural copepod assemblage after exposure to mechanically or chemically dispersed crude oil. Between 88 and 100% of the analyzed fecal pellets from three species of copepods and a natural copepod assemblage exposed for 48 h to physically or chemically dispersed light crude oil contained crude oil droplets. Crude oil droplets inside fecal pellets were smaller (median diameter: 2.4–3.5 μm) than droplets in the physically and chemically dispersed oil emulsions (median diameter: 6.6 and 8.0 μm, respectively). This suggests that copepods can reject large crude oil droplets or that crude oil droplets are broken into smaller oil droplets before or during ingestion. Depending on the species and experimental treatments, crude oil defecation rates ranged from 5.3 to 245 ng-oil copepod"−"1 d"−"1, which represent a mean weight-specific defecation rate of 0.026 μg-oil μg-C_c_o_p_e_p_o_d"1 d"−"1. Considering a dispersed crude oil concentration commonly found in the water column after oil spills (1 μl L"−"1) and copepod abundances in high productive coastal areas, copepods may defecate ∼1.3–2.6 mg-oil m"−"3 d"−"1, which would represent ∼0.15%–0.30% of the total dispersed oil per day. Our results indicate that ingestion and subsequent defecation of crude oil by planktonic copepods has a small influence on the overall mass of oil spills in the short term, but may be quantitatively important in the flux of oil from surface water to sediments and in the transfer of low-solubility, toxic petroleum hydrocarbons into food webs after crude oil spills in the sea. - Highlights: • Copepods exposed to dispersed crude oil produced fecal pellets contained numerous small oil droplets (2.4 to 3.5 µm). • Copepods could reject large oil droplets or oil droplets are broken into

Determining the Advantages, Costs, and Trade-Offs of a Novel Sodium Channel Mutation in the Copepod Acartia hudsonica to Paralytic Shellfish Toxins (PST.

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Michael Finiguerra

Full Text Available The marine copepod Acartia hudsonica was shown to be adapted to dinoflagellate prey, Alexandrium fundyense, which produce paralytic shellfish toxins (PST. Adaptation to PSTs in other organisms is caused by a mutation in the sodium channel. Recently, a mutation in the sodium channel in A. hudsonica was found. In this study, we rigorously tested for advantages, costs, and trade-offs associated with the mutant isoform of A. hudsonica under toxic and non-toxic conditions. We combined fitness with wild-type: mutant isoform ratio measurements on the same individual copepod to test our hypotheses. All A. hudsonica copepods express both the wild-type and mutant sodium channel isoforms, but in different proportions; some individuals express predominantly mutant (PMI or wild-type isoforms (PWI, while most individuals express relatively equal amounts of each (EI. There was no consistent pattern of improved performance as a function of toxin dose for egg production rate (EPR, ingestion rate (I, and gross growth efficiency (GGE for individuals in the PMI group relative to individuals in the PWI expression group. Neither was there any evidence to indicate a fitness benefit to the mutant isoform at intermediate toxin doses. No clear advantage under toxic conditions was associated with the mutation. Using a mixed-diet approach, there was also no observed relationship between individual wild-type: mutant isoform ratios and among expression groups, on both toxic and non-toxic diets, for eggs produced over three days. Lastly, expression of the mutant isoform did not mitigate the negative effects of the toxin. That is, the reductions in EPR from a toxic to non-toxic diet for copepods were independent of expression groups. Overall, the results did not support our hypotheses; the mutant sodium channel isoform does not appear to be related to adaptation to PST in A. hudsonica. Other potential mechanisms responsible for the adaptation are discussed.

Toxicity of some heavy metals to copepods Acartia spinicauda and Tortanus forcipatus

Digital Repository Service at National Institute of Oceanography (India)

Madhupratap, M.; Achuthankutty, C.T.; Nair, S.R.S.

Copper was most toxic to the species tested followed by cadmium and zinc The estuarine species Acartia spinicauda was more sensitive to the toxicants that the marine species Tortanus forcipatus The 48 hr LC50 values are presented....

Ocean acidification challenges copepod phenotypic plasticity

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A. Vehmaa

2016-11-01

Full Text Available Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC as a function of acidification (fCO2  ∼  365–1231 µatm and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm or quality (C : N weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

Zooplankton Hydrodynamics

DEFF Research Database (Denmark)

Wadhwa, Navish

flow disturbances that may attract predators. The first part of this thesis attempts to quantify the trade-offs associated with the swimming behaviour of diverse zooplankton. We measured the swimming kinematics and flow fields around the 'jumping' copepod Acartia tonsa at various stages of its life....... We studied how sensing modes and their respective ranges depend on body size. We investigated the physiological constraints on sense organs, together with the physics of signal generation, transmission, and reception. Our analysis revealed a hierarchy of sensing modes - with increasing size, a larger...

Effect of heterotrophic versus autotrophic food on feeding and reproduction of the calanoid copepod Acartia tonsa : relationship with prey fatty acid composition

DEFF Research Database (Denmark)

Broglio, E.; Jonasdottir, Sigrun; Calbet, A.

2003-01-01

Gymnodinium sanguineum. The diets were also analyzed for fatty acid contents and composition, relationships with EPE and reproductive success were determined. Clear differences were found in the fatty acid contents and the composition of the different diets offered, but these differences did not correspond...... with variability in EPE. However, egg viability was correlated with ingestion of certain prey essential fatty acids; interestingly, our data do not show that ciliates and heterotrophic dinoflagellates are nutritionally superior prey for marine copepods, contrary to general expectations....

Applied and fundamental plankton research would benefit from more joint efforts

DEFF Research Database (Denmark)

Hansen, Benni Winding; Jepsen, Per Meyer; Drillet, Guillaume

2017-01-01

Increased collaboration and communication is needed between the planktologists engaged in marine ecological research and those working with industrial applications. Lessening the dichotomy between “basic” and “applied” sciences will lead to increase scientific advances in both fields. Thanks...... to dedicated research efforts, industrial production of rotifers, Artemia and, more recently, copepods as live feed for fish hatcheries is established. Yet, there are still many biological and technical challenges to be tackled for optimizing production. Some of these challenges could be eliminated faster...... examples from research carried out to support aquaculture production of the cosmopolitan calanoid copepod Acartia tonsa. We argue that research questions are often answered using similar experimental approaches and quality standards; and that scientists working across different fields would gain by more...

Influence of LAS on marine calanoid copepod population dynamics and potential reproduction

DEFF Research Database (Denmark)

Christoffersen, Kirsten; Hansen, Benni Winding; Johansson, Liselotte Sander

2003-01-01

The toxicity of linear alkyl benzene sulfonate (LAS) to marine invertebrates is well documented under laboratory conditions using single-species tests. It is less known how LAS affects natural populations of aquatic organisms. We hypothesised that LAS was more toxic to the calanoid copepod Acartia...

Estudio anual del zooplancton: composición, abundancia, biomasa e hidrología del norte de Quintana Roo, mar Caribe de México Annual study of zooplankton: composition, abundance, biomass and hydrology from the north of Quintana Roo, Mexican Caribbean Sea

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José N Álvarez-Cadena

2007-12-01

Full Text Available Se llevaron a cabo muestreos de zooplancton en la zona lagunar y costera del Caribe mexicano, desde Puerto Morelos hasta Cancún. Las recolectas se llevaron a cabo de enero a diciembre de 2004 en 12 localidades. Se identificaron 41 grupos del zooplancton donde los copépodos fueron los más abundantes (61% seguidos de las larvas de equinodermos (17% y decápodos (5%. El copépodo Acartia tonsa fue la especie más abundante de este grupo en el Sistema Lagunar Nichupté (SLN. En la zona marina adyacente los copépodos estuvieron representados en orden de importancia por Acartia spinata, Pseudocalanus sp. y Calanopia americana. En todas las estaciones se capturaron equinodermos del tipo equinopluteus-ofiopluteus, pero con mayor abundancia en el SLN. El quetognato Ferosagitta hispida fue la única especie que se encontró en el SLN, donde fue más abundante. Los decápodos estuvieron representados principalmente por larvas zoeas; las larvas de peces por 54 familias, de las cuales los góbidos de los géneros Ctenogobius sp., Gobionellus sp. y Gobiosoma sp. fueron los mejor representados, particularmente para el SLN. La biomasa fue mayor en el SLN.Zooplankton sampling was carried out in the northern coast of the Mexican Caribbean Sea, from Puerto Morelos to Cancun. Captures were made with a conic net 0.4m diameter, 1.40m length and 0.330 mm mesh from January to December 2004 at twelve locations. A total of 41 zooplankton groups were identified. Copepods were the most abundant taxa making up 61%, followed by echinoderms (17% and decapods (5%. Acartia tonsa at the Nichupte Lagoon System (SLN over numbered the copepod fauna and occasionally the whole zooplankton population. Along the coast Acartia spinata, Pseudocalanus sp, and Calanopia americana were the most important copepods. Echinoderms larvae such as echinopluteus-ophiopluteus were present at all sampled stations but were more abundant at the NLS. For chaetognaths, Ferosagitta hispida dominated

Mesozooplankton grazing on picocyanobacteria in the Baltic Sea as inferred from molecular diet analysis.

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Nisha H Motwani

Full Text Available Our current knowledge on the microbial component of zooplankton diet is limited, and it is generally assumed that bacteria-sized prey is not directly consumed by most mesozooplankton grazers in the marine food webs. We questioned this assumption and conducted field and laboratory studies to examine picocyanobacteria contribution to the diets of Baltic Sea zooplankton, including copepods. First, qPCR targeting ITS-1 rDNA sequence of the picocyanobacteria Synechococcus spp. was used to examine picocyanobacterial DNA occurrence in the guts of Baltic zooplankton (copepods, cladocerans and rotifers. All field-collected zooplankton were found to consume picocyanobacteria in substantial quantities. In terms of Synechococcus quantity, the individual gut content was highest in cladocerans, whereas biomass-specific gut content was highest in rotifers and copepod nauplii. Moreover, the gut content in copepods was positively related to the picocyanobacteria abundance and negatively to the total phytoplankton abundance in the water column at the time of sampling. This indicates that increased availability of picocyanobacteria resulted in the increased intake of this prey and that copepods may rely more on picoplankton when food in the preferred size range declines. Second, a feeding experiments with a laboratory reared copepod Acartia tonsa fed a mixture of the picocyanobacterium Synechococcus bacillaris and microalga Rhodomonas salina confirmed that copepods ingested Synechococcus, even when the alternative food was plentiful. Finally, palatability of the picocyanobacteria for A. tonsa was demonstrated using uptake of (13C by the copepods as a proxy for carbon uptake in feeding experiment with (13C-labeled S. bacillaris. These findings suggest that, if abundant, picoplankton may become an important component of mesozooplankton diet, which needs to be accounted for in food web models and productivity assessments.

Study of the copepods population in the Oum Er Rbia estuary (Atlantic Moroccan coast): tides and reservoir release effects

International Nuclear Information System (INIS)

El Khalki, A.; Moncef, M.

2007-01-01

Variation of environmental parameters and copepods population were studied in the Oum Er Rbia estuary (Atlantic - Moroccan coast) according to the seasons, ( August 1995 to August 1997), tides and reservoir release events. Environemental variability influences copepods diversity and abundance. Salinity (5 to 20 g l-1) appears as the main controlling factor. Among the 27 copepod species recorded, only three marine species (Oithona helgolandica, Euterpina acutifrons, Acartia clausi) and one freshwater species (Acanthocyclops robustus) are able to maintain significant populations due to their large degree of tolerance to salinity changes. (author)

Biological effects of simulated discharge plume entrainment at Indian Point Nuclear Power Station, Hudson River estuary, USA

International Nuclear Information System (INIS)

Lanza, G.R.; Lauer, G.J.; Ginn, T.C.; Storm, P.C.; Zubarik, L.; New York Univ., N.Y.

1975-01-01

Laboratory and field simulations of the discharge plume entrainment of phytoplankton, zooplankton and fish were carried out at the Indian Point Nuclear Station, Hudson River estuary, USA. Phytoplankton assemblages studied on two dates produced different response patterns measured as photosynthetic activity. Chlorophyll-a levels did not change following simulated entrainment. Possible explanations for the differences are discussed. The two abundant copepods Acartia tonsa and Eurytemorta affinis appear to tolerate exposure to discharge plume ΔT without adverse effects. Copepods subjected to plume entrainment may suffer considerable mortality during periods of condenser chlorination. In general, the amphipod Gammarus spp. did not appear to suffer significant mortality during simulated entrainment. Juvenile striped bass, Morone saxatilis, were not affected by simulated plume transit before and during plant condenser chlorination; however, a simulated ''worst possible case'' plume ΔT produced statistically significant moralities. (author)

Copepod egg production, moulting and growth rates and secondary production in the Skagerrak in August 1988

DEFF Research Database (Denmark)

Peterson, W.T.; Tiselius, P.; Kiørboe, Thomas

1991-01-01

Measurements of hydrography, chlorophyll, moulting rates of juvenile copepods and egg production rates of adult female copepods were made at eight stations along a transect across the Skagerrak. The goals of the study were to determine (i) if there were correlations between spatial variations...... in hydrography, phytoplankton and copepod production rates, (ii) if copepod egg production rates were correlated with juvenile growth rates, and (iii) if there was evidence of food-niche separation among co-occurring female copepods. The 200 km wide Skagerrak had a stratified water column in the center...... is similar to maximum rates known from laboratory studies, thus were probably not food-limited. Egg production rates were food-limited with the degree of limitation varying among species: 75% of maximum for Centropages typicus, 50% for Calanus finmarchicus, 30% for Paracalanus parvus and 15% for Acartia...

Effect of alternative mediums on production and proximate composition of the microalgae Chaetoceros muelleri as food in culture of the copepod Acartia sp. Efecto de medios alternativos sobre la producción y composición proximal de la microalga Chaetoceros muelleri como alimento en cultivo del copépodo Acartia sp.

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Luis R Martínez-Córdova

2012-03-01

Full Text Available Microalgae Chaetoceros muelleri was cultured in three different mediums consisting on an agricultural fertilizer (Agr-F, aquacultural fertilizer (Aq-F and a conventional medium (F/2, control. These microalgae were later used as natural food to culture the copepod Acartia sp. The productive response and chemical proximate composition of microalgae and copepods were monitored. Growth rate and final cell concentration were higher in microalgae cultured in Agr-F compared to the control. In addition, the final biomass and cellular concentration were also the highest in Agr-F. Microalgae from Agr-F and Aq-F had higher carbohydrate and lower protein contents than those in the control. No differences in lipid and ash contents were observed. Regarding copepod production, higher densities and fecundity indexes were observed for those fed with microalgae previously cultured in Agr-F and Aq-F, compared to the control. The adult-nauplii ratio was also higher in copepods fed on microalgae from Agr-F compared to Aq-F and control. Copepods fed on Agr-F and Aq-F microalgae, had higher protein content compared to those fed on control microalgae; carbohydrates were higher in copepods fed on Agr-F as compared to Aq-F microalgae. No differences in lipid and ash contents were registered. Agr-F and Aq-F were adequate alternative mediums to produce C. muelleri, which produced higher quality microalgae that increased the copepod production.La microalga Chaetoceros muelleri fue cultivada en tres medios diferentes basados en un fertilizante agrícola (Agr-F, un fertilizante acuícola (Aq-F y un medio convencional (F/2, control. Éstas microalgas fueron posteriormente utilizadas como alimento natural para cultivar el copépodo Acartia sp. La respuesta productiva y la composición proximal de las microalgas y copépodos fueron monitoreadas. La tasa de crecimiento y concentración final de células fueron mayores en la microalga cultivada en Agr-F, comparada con el control

Morphology of seahorse head hydrodynamically aids in capture of evasive prey.

Science.gov (United States)

Gemmell, Brad J; Sheng, Jian; Buskey, Edward J

2013-01-01

Syngnathid fish (seahorses, pipefish and sea dragons) are slow swimmers yet capture evasive prey (copepods) using a technique known as the 'pivot' feeding, which involves rapid movement to overcome prey escape capabilities. However, this feeding mode functions only at short range and requires approaching very closely to hydrodynamically sensitive prey without triggering an escape. Here we investigate the role of head morphology on prey capture using holographic and particle image velocimetry (PIV). We show that head morphology functions to create a reduced fluid deformation zone, minimizing hydrodynamic disturbance where feeding strikes occur (above the end of the snout), and permits syngnathid fish to approach highly sensitive copepod prey (Acartia tonsa) undetected. The results explain how these animals can successfully employ short range 'pivot' feeding effectively on evasive prey. The need to approach prey with stealth may have selected for a head shape that produces lower deformation rates than other fish.

Stable Associations Masked by Temporal Variability in the Marine Copepod Microbiome.

Science.gov (United States)

Moisander, Pia H; Sexton, Andrew D; Daley, Meaghan C

2015-01-01

Copepod-bacteria interactions include permanent and transient epi- and endobiotic associations that may play roles in copepod health, transfer of elements in the food web, and biogeochemical cycling. Microbiomes of three temperate copepod species (Acartia longiremis, Centropages hamatus, and Calanus finmarchicus) from the Gulf of Maine were investigated during the early summer season using high throughput amplicon sequencing. The most prominent stable component of the microbiome included several taxa within Gammaproteobacteria, with Pseudoalteromonas spp. especially abundant across copepod species. These Gammaproteobacteria appear to be promoted by the copepod association, likely benefitting from nutrient enriched microenvironments on copepods, and forming a more important part of the copepod-associated community than Vibrio spp. during the cold-water season in this temperate system. Taxon-specific associations included an elevated relative abundance of Piscirickettsiaceae and Colwelliaceae on Calanus, and Marinomonas sp. in Centropages. The communities in full and voided gut copepods had distinct characteristics, thus the presence of a food-associated microbiome was evident, including higher abundance of Rhodobacteraceae and chloroplast sequences in the transient communities. The observed variability was partially explained by collection date that may be linked to factors such as variable time since molting, gender differences, and changes in food availability and type over the study period. While some taxon-specific and stable associations were identified, temporal changes in environmental conditions, including food type, appear to be key in controlling the composition of bacterial communities associated with copepods in this temperate coastal system during the early summer.

Seasonal variability of planktonic copepods (Copepoda: Crustacea in a tropical estuarine region in Brazil

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Cristina de Oliveira Dias

2009-12-01

Full Text Available The Caravelas River estuary and adjacent coastal region were studied during the rainy and dry seasons of 2003-2004 to assess the copepod community structure. Abiotic and biotic parameters were measured, and the total density, frequency and percentage of copepod taxa were determined for each sampling period. Copepod densities showed significant differences between sampling periods, with higher densities in the rainy seasons (Mean: 90,941.80 ind.m-3; S.D.: 26,364.79. The sampling stations located to the north and south, in the coastal region adjacent to the Caravelas River estuary presented the lowest copepod density values. The copepod assemblage was composed mainly of estuarine and estuarine/coastal copepods. The seasonal variations in temperature and salinity influenced the abundance of species during the rainy and dry seasons, with the following dominant species alternating: Paracalanus quasimodo Bowman, 1971 in the rainy season of 2003, Parvocalanus crassirostris Dahl, 1894 in the dry season of 2003 and Acartia lilljeborgii Giesbrecht, 1892 in the rainy and dry seasons of 2004. Non-parametric multidimensional scaling indicated differences in copepod assemblages between sampling periods, but not between sampling stations.

Uptake, absorption efficiency and elimination of DDT in marine phytoplankton, copepods and fish

International Nuclear Information System (INIS)

Wang Xinhong; Wang Wenxiong

2005-01-01

Uptake, absorption efficiency and elimination of DDT were measured in marine phytoplankton, copepods (Acartia erythraea) and fish (mangrove snappers Lutjanus argentimaculatus). The uptake rate constant of DDT from water decreased with increasing trophic level. The dietary absorption efficiency (AE) of DDT was 10-29% in copepods and 72-99% in fish. Food concentration did not significantly affect the AEs of DDT, but the AEs varied considerably among the different food diets. The elimination rate constants of DDT by the copepods were comparable following uptake from the diet and from the water. Elimination of DDT from the fish was exceedingly low. Both aqueous and dietary uptake are equally important for DDT accumulation in the copepods. In fish, dissolved exposure is a more significant route than intake from the diet. The predicted trophic transfer factors in the copepods and the fish are consistent with the field measurements in marine zooplankton and fish. -Biomagnification and exposure of DDT in a marine food chain is demonstrated by measurements of uptake and elimination rates and kinetic modeling

Ocean acidification challenges copepod reproductive plasticity

Science.gov (United States)

Vehmaa, A.; Almén, A.-K.; Brutemark, A.; Paul, A.; Riebesell, U.; Furuhagen, S.; Engström-Öst, J.

2015-11-01

Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia bifilosa in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ~ 365-1231 μatm), and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal if transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female copepod size and egg hatching success. In addition, we found a threshold of fCO2 concentration (~ 1000 μatm), above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon ~ 55 μm) or quality (C : N) weakens the transgenerational effects. However, females with high ORAC produced eggs with high hatching success. Overall, these results indicate that A. bifilosa could be affected by projected near future CO2 levels.

Distribución del zooplancton durante flujos de marea opuestos en el complejo lagunar de Chelem, Yucatán, México

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J.B. Escamilla

2001-03-01

Full Text Available Zooplankton was surveyed in a tropical lagoon system of the northern coast of the Yucatan Peninsula in high tide, December (1998 and low tide, March 1999 (northerlies season. Zooplankton biomass was measured, zooplankters were counted, and copepods were identified and quantified. Despite the fact that both months were influenced by winds from the North, they showed a different salinity gradient which developed a particular structure of the zooplankton community. Biomass tended to be accumulated in certain areas apparently because of the high residence time of water in Chelem, the forcing effect of the northerlies, and of the tidal current. Biomass values suggest a relatively high secondary production when compared with other systems of the Yucatan Peninsula. The distribution of the copepods Acartia lilljeborgii and A. tonsa is related to saline conditions and tidal flow. The overall faunistic and hydrologic data suggest that even during a single climatic season, the zooplankton community shows strong changes due to mesoscale hydrological processes.

Observation on Marine Copepod - Appendicularian Naturally Changing Concentrations Along Southwest Coast of India

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Jean J. JOSE

2012-11-01

Full Text Available Patterns of copepod - appendicularian distribution were studied along the Mangalore coastal waters (12�50�49� N; 74�48�50� E of the Arabian Sea to understand the food and feeding relationship existing among these groups. Sampling was conducted during pre-monsoon, monsoon and post-monsoon extending from January 2009 to December 2010. The copepod and appendicularian community was sampled with a 60 ?m net to include the smallest species and their developmental stages. Copepod biomass, especially calanoids, was substantially high throughout the study. Seasonal mean results showed that the small-sized copepods (calanoids, harpacticoida and cyclopoids dominated in terms of biomass and production. Calanoids found in abundance included Acartia, Centropages, Calanus, Eucalanus and Labidocera. Cyclopoid and Harpacticoid copepods genera dominated included Oithona, Oncaea and Microsetella, Macrosetella. Appendicularian species diversity was represented by Oikopleura fusiformis, O. dioica and its juveniles represented as Oikopleura sp. Total chlorophyll (chlorophyll a ranging between 10 and 20 mg m-3 indicated the eutrophic state as well as productivity prevailing during the study period. Principal component analysis (PCA indicated the routine and opportunistic seasonal grazers and establishes a phytoplankton - appendicularia - copepod - fish food chain relationship along Mangalore coast.

Escape response of planktonic protists to fluid mechanical signals

DEFF Research Database (Denmark)

Jakobsen, Hans Henrik

2001-01-01

The escape response to fluid mechanical signals was examined in 6 protists, 4 ciliates and 2 dinoflagellates. When exposed to a siphon flow. 3 species of ciliates, Balanion comatum, Strobilidium sp., and Mesodinium pulex, responded with escape jumps. The threshold deformation rates required...... times lower than that of a non-jumping similar sized protist when the predator was Temora longicornis, which captures prey entrained in a feeding current. However, when the predator was the ambush- feeding copepod Acartia tonsa, the predation mortalities of jumping and non-jumping protists were...... of similar magnitude. Escape responses may thus be advantageous in some situations. However, jumping behaviour may also enhance susceptibility to some predators, explaining the different predator avoidance strategies (jumping or not) that have evolved in planktonic protists....

Interactions between zooplankton and crude oil: toxic effects and bioaccumulation of polycyclic aromatic hydrocarbons.

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Rodrigo Almeda

Full Text Available We conducted ship-, shore- and laboratory-based crude oil exposure experiments to investigate (1 the effects of crude oil (Louisiana light sweet oil on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs in mesozooplankton communities, (2 the lethal effects of dispersant (Corexit 9500A and dispersant-treated oil on mesozooplankton, (3 the influence of UVB radiation/sunlight exposure on the toxicity of dispersed crude oil to mesozooplankton, and (4 the role of marine protozoans on the sublethal effects of crude oil and in the bioaccumulation of PAHs in the copepod Acartia tonsa. Mortality of mesozooplankton increased with increasing oil concentration following a sigmoid model with a median lethal concentration of 32.4 µl L(-1 in 16 h. At the ratio of dispersant to oil commonly used in the treatment of oil spills (i.e. 1∶20, dispersant (0.25 µl L(-1 and dispersant-treated oil were 2.3 and 3.4 times more toxic, respectively, than crude oil alone (5 µl L(-1 to mesozooplankton. UVB radiation increased the lethal effects of dispersed crude oil in mesozooplankton communities by 35%. We observed selective bioaccumulation of five PAHs, fluoranthene, phenanthrene, pyrene, chrysene and benzo[b]fluoranthene in both mesozooplankton communities and in the copepod A. tonsa. The presence of the protozoan Oxyrrhis marina reduced sublethal effects of oil on A. tonsa and was related to lower accumulations of PAHs in tissues and fecal pellets, suggesting that protozoa may be important in mitigating the harmful effects of crude oil exposure in copepods and the transfer of PAHs to higher trophic levels. Overall, our results indicate that the negative impact of oil spills on mesozooplankton may be increased by the use of chemical dispersant and UV radiation, but attenuated by crude oil-microbial food webs interactions, and that both mesozooplankton and protozoans may play an important role in fate of PAHs in marine environments.

Interactions between Zooplankton and Crude Oil: Toxic Effects and Bioaccumulation of Polycyclic Aromatic Hydrocarbons

Science.gov (United States)

Almeda, Rodrigo; Wambaugh, Zoe; Wang, Zucheng; Hyatt, Cammie; Liu, Zhanfei; Buskey, Edward J.

2013-01-01

We conducted ship-, shore- and laboratory-based crude oil exposure experiments to investigate (1) the effects of crude oil (Louisiana light sweet oil) on survival and bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in mesozooplankton communities, (2) the lethal effects of dispersant (Corexit 9500A) and dispersant-treated oil on mesozooplankton, (3) the influence of UVB radiation/sunlight exposure on the toxicity of dispersed crude oil to mesozooplankton, and (4) the role of marine protozoans on the sublethal effects of crude oil and in the bioaccumulation of PAHs in the copepod Acartia tonsa. Mortality of mesozooplankton increased with increasing oil concentration following a sigmoid model with a median lethal concentration of 32.4 µl L−1 in 16 h. At the ratio of dispersant to oil commonly used in the treatment of oil spills (i.e. 1∶20), dispersant (0.25 µl L−1) and dispersant- treated oil were 2.3 and 3.4 times more toxic, respectively, than crude oil alone (5 µl L−1) to mesozooplankton. UVB radiation increased the lethal effects of dispersed crude oil in mesozooplankton communities by 35%. We observed selective bioaccumulation of five PAHs, fluoranthene, phenanthrene, pyrene, chrysene and benzo[b]fluoranthene in both mesozooplankton communities and in the copepod A. tonsa. The presence of the protozoan Oxyrrhis marina reduced sublethal effects of oil on A. tonsa and was related to lower accumulations of PAHs in tissues and fecal pellets, suggesting that protozoa may be important in mitigating the harmful effects of crude oil exposure in copepods and the transfer of PAHs to higher trophic levels. Overall, our results indicate that the negative impact of oil spills on mesozooplankton may be increased by the use of chemical dispersant and UV radiation, but attenuated by crude oil-microbial food webs interactions, and that both mesozooplankton and protozoans may play an important role in fate of PAHs in marine environments. PMID:23840628

Fight and flight in dinoflagellates?

DEFF Research Database (Denmark)

Selander, Erik; Fagerberg, Tony; Wohlrab, Sylke

2012-01-01

We monitored the kinetics of grazer-induced responses in the marine dinoflagellate Alexandrium tamarense. Chemical cues from each of three calanoid copepods (Calanus sp., Centropages typicus, and Acartia tonsa) induced increased toxicity and suppressed chain formation in A. tamarense. Both chemical...... and morphological responses augmented over 3 d. Toxicity subsequently averaged 299% higher than controls, and average biovolume 24% lower than controls because of suppression of chain formation in grazed treatments. Grazer-induced toxicity returned to control levels after approximately 11 d, equivalent to five cell...... that the inducing cue(s) attenuate rapidly in seawater, which allows A. tamarense to adjust resource allocation to grazer-induced responses to follow fluctuations in grazer density. Grazer-induced responses, however, develop too slowly to be accounted for in short-term grazing experiments with laboratory cultures...

Nutritional quality of two cyanobacteria : How rich is 'poor' food?

DEFF Research Database (Denmark)

Schmidt, K.; Jonasdottir, Sigrun

1997-01-01

Cyanobacteria have often been described to be nutritionally inadequate and to interfere with zooplankton feeding. In laboratory experiments we offered 2 cyanobacteria, a unicellular Microcystis aeruginosa strain and the filamentous Nodularia sprumigena, to the calanoid copepod Acartia tonsa...... as the sole diet and in food mixtures with the nutritious diatom Thalassiosira weissflogii. Egg production was used as criterion of food quality. The use of cyanobacteria alone was an insufficient diet. However, with increasing additions of M. aeruginosa and N. spumigena to the diatom, different effects were...... observed. Large additions of cyanobacteria resulted in lower egg production and often in elevated mortality of the females, but small additions of M. aeruginosa caused an increase of about 25 % in egg production compared to a pure diatom diet. The influence of similar low concentrations of N. spumigena...

Experimental Investigation of 3-D flow fields around the mouth of the Dwarf Seahorse during attacks on planktonic prey

Science.gov (United States)

Gemmell, Brad; Buskey, Edward; Sheng, Jian

2009-11-01

Copepods are an important planktonic food source for fish species. High predation has led to the development of effective escape responses with short reaction times (less than 2 ms), maximum escape velocities of over 500 body lengths per second and shear sensitivity as low as 1.5s-1. Using high speed digital holography (2 kfps), we measure 3-D distributions of velocity generated by a dwarf seahorse (Hippocampus zosterae) during attacks on its copepod prey, Acartia tonsa. It is found that successful attacks often produce smaller or even no detectable hydrodynamic disturbances around the strike zone, when compared to unsuccessful attempts. In this paper, we will provide quantitative characterization of this ``low-flow'' zone. Further, to elucidate the role of a possible geometrical advantage of the seahorse's head in minimizing its bow wave, high-speed time resolved PIV measurements are conducted in a low-speed water tunnel. On-going analysis will provide insights and implications in understanding the dynamics of flows around the stagnation point at high Reynolds number flow. Sponsored by NSF.

Tests for oil/dispersant toxicity: In situ laboratory assays

International Nuclear Information System (INIS)

Wright, D.A.; Coelho, G.M.; Aurand, D.V.

1995-01-01

As part of its readiness program in oil spill response, the Marine Pollution Control Unit (MPCU), Department of Transport, U.K. conducts annual field trials in the North Sea, approximately 30 nautical miles from the southeast coast of England. The trials take the form of controlled releases of crude oil or Medium Fuel/Gas Oil mix (MFO), with and without the application of Corexit 9527 dispersant. In 1994 and 1995 the authors conducted a series of in situ toxicity bioassays in association with these spills with included 48h LC50 tests for turbot (Scophthalmus maximus) and oyster (Crassostrea gigas) larvae, a 48 h oyster (C. gigas) embryonic development test and two full life-cycle assays using the copepods Acartia tonsa and Tisbe battagliai. Tests were also conducted in the Chesapeake Bay laboratory using estuarine species including the copepod Eurytemora affinis and the inland silverside Menidia beryllina. Here, the authors report on the results of these assays, together with 1996 in situ toxicity data resulting from Norwegian field trials in the northern North Sea

Variability in copepod trophic levels and feeding selectivity based on stable isotope analysis in Gwangyang Bay of the southern coast of the Korean Peninsula

Science.gov (United States)

Chen, Mianrun; Kim, Dongyoung; Liu, Hongbin; Kang, Chang-Keun

2018-04-01

Trophic preference (i.e., food resources and trophic levels) of different copepod groups was assessed along a salinity gradient in the temperate estuarine Gwangyang Bay of Korea, based on seasonal investigation of taxonomic results in 2015 and stable isotope analysis incorporating multiple linear regression models. The δ13C and δ15N values of copepods in the bay displayed significant spatial heterogeneity as well as seasonal variations, which were indicated by their significant relationships with salinity and temperature, respectively. Both spatial and temporal variations reflected those in isotopic values of food sources. The major calanoid groups (marine calanoids and brackish water calanoids) had a mean trophic level of 2.2 relative to nanoplankton as the basal food source, similar to the bulk copepod assemblage; however, they had dissimilar food sources based on the different δ13C values. Calanoid isotopic values indicated a mixture of different genera including species with high δ15N values (e.g., Labidocera, Sinocalanus, and Tortanus), moderate values (Calanus sinicus, Centropages, Paracalanus, and Acartia), and relatively low δ15N values (Eurytemora pacifica and Pseudodiaptomus). Feeding preferences of different copepods probably explain these seasonal and spatial patterns of the community trophic niche. Bayesian mixing model calculations based on source materials of two size fractions of particulate organic matter (nanoplankton at simple energy flow of the planktonic food web of Gwangyang Bay: from primary producers (nanoplankton) and a mixture of primary producers and herbivores (microplankton) through omnivores (Acartia, Calanus, Centropages, and Paracalanus) and detritivores (Pseudodiaptomus, Eurytemora, and harpacticoids) to carnivores (Corycaeus, Tortanus, Labidocera, and Sinocalanus).

What factors drive copepod community distribution in the Gulf of Gabes, Eastern Mediterranean Sea?

Science.gov (United States)

Drira, Zaher; Bel Hassen, Malika; Ayadi, Habib; Aleya, Lotfi

2014-02-01

The spatial and temporal variations in copepod communities were investigated during four oceanographic cruises conducted between July 2005 and March 2007 aboard the R/V Hannibal. A close relationship was observed between the temperature, salinity, hydrographic properties and water masses characterising the Gulf of Gabes. Indeed, water thermal stratification began in May-June, and a thermocline was established at a 20-m depth, but ranged from 25 m in July to more than 30 m in September. The zooplankton community is dominated by copepods representing 69 % to 83 % of total zooplankton. Spatial and temporal variation of copepods in relation to environmental factors shows their close relationship with the hydrodynamic features of the water column. Thermal stratification in the column, established in summer, supports copepod development. In fact, copepod abundance increases gradually with rising water temperature and salinity, starting from the beginning of thermal stratification (May-June 2006) and lasting until its completion (July 2005 and September 2006). When the water column is well mixed (March 2007), copepod abundance decreased. Our finding shows that temperature and salinity seem to be the most important physical factors and thus strongly influence the taxonomic diversity and distribution of the copepod population. They are characterised by the dominance of Oithona nana, representing 75-86 % of total cyclopoid abundance. The most abundant species during the stratification period were O. nana, Acartia clausi and Stephos marsalensis in July 2005 and September 2006. However, during the mixing period, Euterpina acutifrons was more abundant, representing 21 % of the total. Unlike the copepod community, which is more abundant during the period of high stratification, phytoplankton proliferates during semi-mixed conditions.

Ocean acidification-induced food quality deterioration constrains trophic transfer.

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Dennis Rossoll

Full Text Available Our present understanding of ocean acidification (OA impacts on marine organisms caused by rapidly rising atmospheric carbon dioxide (CO(2 concentration is almost entirely limited to single species responses. OA consequences for food web interactions are, however, still unknown. Indirect OA effects can be expected for consumers by changing the nutritional quality of their prey. We used a laboratory experiment to test potential OA effects on algal fatty acid (FA composition and resulting copepod growth. We show that elevated CO(2 significantly changed the FA concentration and composition of the diatom Thalassiosira pseudonana, which constrained growth and reproduction of the copepod Acartia tonsa. A significant decline in both total FAs (28.1 to 17.4 fg cell(-1 and the ratio of long-chain polyunsaturated to saturated fatty acids (PUFA:SFA of food algae cultured under elevated (750 µatm compared to present day (380 µatm pCO(2 was directly translated to copepods. The proportion of total essential FAs declined almost tenfold in copepods and the contribution of saturated fatty acids (SFAs tripled at high CO(2. This rapid and reversible CO(2-dependent shift in FA concentration and composition caused a decrease in both copepod somatic growth and egg production from 34 to 5 eggs female(-1 day(-1. Because the diatom-copepod link supports some of the most productive ecosystems in the world, our study demonstrates that OA can have far-reaching consequences for ocean food webs by changing the nutritional quality of essential macromolecules in primary producers that cascade up the food web.

Ocean acidification-induced food quality deterioration constrains trophic transfer.

Science.gov (United States)

Rossoll, Dennis; Bermúdez, Rafael; Hauss, Helena; Schulz, Kai G; Riebesell, Ulf; Sommer, Ulrich; Winder, Monika

2012-01-01

Our present understanding of ocean acidification (OA) impacts on marine organisms caused by rapidly rising atmospheric carbon dioxide (CO(2)) concentration is almost entirely limited to single species responses. OA consequences for food web interactions are, however, still unknown. Indirect OA effects can be expected for consumers by changing the nutritional quality of their prey. We used a laboratory experiment to test potential OA effects on algal fatty acid (FA) composition and resulting copepod growth. We show that elevated CO(2) significantly changed the FA concentration and composition of the diatom Thalassiosira pseudonana, which constrained growth and reproduction of the copepod Acartia tonsa. A significant decline in both total FAs (28.1 to 17.4 fg cell(-1)) and the ratio of long-chain polyunsaturated to saturated fatty acids (PUFA:SFA) of food algae cultured under elevated (750 µatm) compared to present day (380 µatm) pCO(2) was directly translated to copepods. The proportion of total essential FAs declined almost tenfold in copepods and the contribution of saturated fatty acids (SFAs) tripled at high CO(2). This rapid and reversible CO(2)-dependent shift in FA concentration and composition caused a decrease in both copepod somatic growth and egg production from 34 to 5 eggs female(-1) day(-1). Because the diatom-copepod link supports some of the most productive ecosystems in the world, our study demonstrates that OA can have far-reaching consequences for ocean food webs by changing the nutritional quality of essential macromolecules in primary producers that cascade up the food web.

Combined toxicity effects of chlorine, ammonia, and temperature on marine plankton. Progress report, November 1976--31 January 1978

Energy Technology Data Exchange (ETDEWEB)

Goldman, J. C.

1978-02-01

Studies on the effects of chlorine, chloramines, and temperature on marine plankton have been carried out for three years. Species studied include marine phytoplankton, lobster larvae (Homarus americanus), oyster larvae (Crassostrea virginica), copepods (Acartia tonsa), rotifers (Brachionas plicatilis), grass shrimp (Palamonetes pugio) summer flounder larvae (Paralichthys dentatus), larval and juvenile killifish (Fundulus heteroclitus), juvenile scup (Stenotomus versicolor), and juvenile winter flounder (Pseudopleuronectes americanus). In addition extensive studies on chlorine chemistry in seawater have been carried out. The major conclusions are that entrainment effects on permanent plankton such as phytoplankton, copepods, and rotifers are temporary, that is those organisms surviving chlorination and temperature shocks are capable of renewed and unrestricted growth once returned to the receiving water. Because chlorine is only applied for short periods daily in most power plants, the total population of the above organisms actually exposed to chlorine is small and the effects may be hardly measurable in receiving waters. However, chlorination effects on larval species that spawn intermittently could be catastrophic. In addition, there are many unanswered questions regarding the fate of chlorine that is dissipated in marine waters. Are the losses real and, if so, do they pose a toxicity threat to marine biota.

Influence of environmental conditions on the toxicokinetics of cadmium in the marine copepod Acartia tonsa

NARCIS (Netherlands)

Pavlaki, Maria D.; Morgado, Rui G.; van Gestel, Cornelis A.M.; Calado, Ricardo; Soares, Amadeu M.V.M.; Loureiro, Susana

2017-01-01

mMarine and estuarine ecosystems are highly productive areas that often act as a final sink for several pollutants, such as cadmium. Environmental conditions in these habitats can affect metal speciation, as well as its uptake and depuration by living organisms. The aim of this study was to assess

Response of marine copepods to a changing tropical environment: winners, losers and implications.

Science.gov (United States)

Chew, Li Lee; Chong, Ving Ching

2016-01-01

Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985-86 and 2014-15) interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI) design. Copepods were identified to species, and results were interpreted by univariate (ANOVA) and multivariate (PERMANOVA, PCO) analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus) were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica). Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons) were unaffected. Centropages

Response of marine copepods to a changing tropical environment: winners, losers and implications

Directory of Open Access Journals (Sweden)

Li Lee Chew

2016-05-01

Full Text Available Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985–86 and 2014–15 interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI design. Copepods were identified to species, and results were interpreted by univariate (ANOVA and multivariate (PERMANOVA, PCO analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica. Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons were unaffected

Response of marine copepods to a changing tropical environment: winners, losers and implications

Science.gov (United States)

Chew, Li Lee

2016-01-01

Background. Climate change concurrent with anthropogenic disturbances can initiate serial changes that reverberate up the food chain with repercussions for fisheries. To date, there is no information available concerning the combined effects of global warming and human impacts on tropical marine food webs. While temperate copepods respond differently to warming and environmental stressors, the extent to which tropical copepods can adapt to rising temperature of already warm waters remains unknown. We hypothesize that sea warming and other anthropogenic disturbances over the long term will have the greatest impact on the copepod community in nearshore waters where their effects are accentuated, and therefore vulnerable and resilient species could be identified. Methods. Zooplankton samples were collected during two time periods (1985–86 and 2014–15) interposed by marked anthropogenic disturbances, and at the same five stations located progressively from inshore to offshore in Klang Strait, Malaysia, following the asymmetrical before-after-control-impact (BACI) design. Copepods were identified to species, and results were interpreted by univariate (ANOVA) and multivariate (PERMANOVA, PCO) analyses of the computed species abundance and diversity measures. Results. Copepod total abundance was not significantly different among stations but higher after disturbance than before disturbance. However, changes in the abundance of particular species and the community structure between time periods were dramatic. Coastal large-bodied calanoid species (e.g., Acartia spinicauda, Calanopia thompsoni, Pseudodiaptomus bowmani and Tortanus forcipatus) were the most vulnerable group to disturbance. This however favored the opportunistic species (e.g., Oithona simplex, O. attenuata, Hemicyclops sp., Pseudomacrochiron sp. and Microsetella norvegica). Small-bodied copepods (e.g., Paracalanus sp., Parvocalanus crassirostris and Euterpina acutifrons) were unaffected. Centropages

Differential interactions between the nematocyst-bearing mixotrophic dinoflagellate Paragymnodinium shiwhaense and common heterotrophic protists and copepods: Killer or prey.

Science.gov (United States)

Jeong, Hae Jin; Kim, Jae Seong; Lee, Kyung Ha; Seong, Kyeong Ah; Yoo, Yeong Du; Kang, Nam Seon; Kim, Tae Hoon; Song, Jae Yoon; Kwon, Ji Eun

2017-02-01

To investigate interactions between the nematocyst-bearing mixotrophic dinoflagellate Paragymnodinium shiwhaense and different heterotrophic protist and copepod species, feeding by common heterotrophic dinoflagellates (Oxyrrhis marina and Gyrodinium dominans), naked ciliates (Strobilidium sp. approximately 35μm in cell length and Strombidinopsis sp. approximately 100μm in cell length), and calanoid copepods Acartia spp. (A. hongi and A. omorii) on P. shiwhaense was explored. In addition, the feeding activities of P. shiwhaense on these heterotrophic protists were investigated. Furthermore, the growth and ingestion rates of O. marina, G. dominans, Strobilidium sp., Strombidinopsis sp., and Acartia spp. as a function of P. shiwhaense concentration were measured. O. marina, G. dominans, and Strombidinopsis sp. were able to feed on P. shiwhaense, but Strobilidium sp. was not. However, the growth rates of O. marina, G. dominans, Strobilidium sp., and Strombidinopsis sp. feeding on P. shiwhaense were very low or negative at almost all concentrations of P. shiwhaense. P. shiwhaense frequently fed on O. marina and Strobilidium sp., but did not feed on Strombidinopsis sp. and G. dominans. G. dominans cells swelled and became dead when incubated with filtrate from the experimental bottles (G. dominans+P. shiwhaense) that had been incubated for one day. The ingestion rates of O. marina, G. dominans, and Strobilidium sp. on P. shiwhaense were almost zero at all P. shiwhaense concentrations, while those of Strombidinopsis sp. increased with prey concentration. The maximum ingestion rate of Strombidinopsis sp. on P. shiwhaense was 5.3ngC predator -1 d -1 (41 cells predator -1 d -1 ), which was much lower than ingestion rates reported in the literature for other mixotrophic dinoflagellate prey species. With increasing prey concentrations, the ingestion rates of Acartia spp. on P. shiwhaense increased up to 930ngCml -1 (7180cellsml -1 ) at the highest prey concentration. The

Composition of the zooplankton community,with emphasis in copepods, in Punta Morales,Golfo de Nicoya,Costa Rica

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Ernesto Brugnoli-Olivera

2004-12-01

Full Text Available The composition of the mesozooplanktonic community was studied in the Punta Morales estuary, Gulf of Nicoya,Pacific coast of Costa Rica,during 1997.Oblique plankton hauls were performed during high and low tide using a 280 µm mesh screen net equipped with a flowmeter.The community was characterized by holoplanktonic and meroplanktonic organisms.For the holoplanktonic community,the main groups were copepods (80%and chaetognaths (16%.The most abundant species were the copepods Acartia lilljeborgii and Paracalanus parvus.A.lilljeborgii is a typical estuarine species that maintains high populations in estuarine systems.Meroplankton was represented mainly by crustacean larvae (66%,and icthyoplankton (18%.The dominance of crustacean larvae and icthyoplankton is an evidence of the ecological importance of the Punta Morales zone.Rev.Biol.Trop.52(4:897-902.Epub 2005 Jun 24.Se estudió la composición de la comunidad mezoplanctónica en Punta Morales,Golfo de Nicoya, Pacífico de Costa Rica,en 1997,arrastrando oblicuamente una red de plancton (280 µm,con flujómetrodurante marea alta y baja.La comunidad estuvo caracterizada por la presencia de organismos holo y meroplanctónicos.Los principales grupos holoplanctónicos fueron copépodos (80%y quetognatos (16%.Las especies más abundantes fueron los copépodos Acartia lilljeborgii y Paracalanus parvus;A. lilljeborgii es una especie estuarina típica que mantiene altas poblaciones en sistemas estuarinos.El meroplancton estuvo representado principalmente por larvas de crustáceos (66%,e ictioplancton (18%.La dominancia de larvas de crustáceos e ictioplancton evidencian la importancia ecológica de la zona de Punta Morales.

Man-induced hydrological changes, metazooplankton communities and invasive species in the Berre Lagoon (Mediterranean Sea, France)

International Nuclear Information System (INIS)

Delpy, Floriane; Pagano, Marc; Blanchot, Jean; Carlotti, François; Thibault-Botha, Delphine

2012-01-01

The Berre Lagoon has been under strong anthropogenic pressure since the early 1950s. The opening of the hydroelectric EDF power plant in 1966 led to large salinity drops. The zooplankton community was mainly composed of two common brackish species: Acartia tonsa and Brachionus plicatilis. Since 2006, European litigation has strongly constrained the input of freshwater, maintaining the salinity above 15. A study was performed between 2008 and 2010 to evaluate how these modifications have impacted the zooplankton community. Our results show that the community is more diverse and contains several coastal marine species (i.e., Centropages typicus, Paracalanus parvus and Acartia clausi). A. tonsa is still present but is less abundant, whereas B. plicatilis has completely disappeared. Strong predatory marine species, such as chaetognaths, the large conspicuous autochtonous jellyfish Aurelia aurita and the invasive ctenophore Mnemiopsis leidyi, are now very common as either seasonal or permanent features of the lagoon.

Environmental stress responses and experimental handling artifacts of a model organism, the copepod Acartia tonsa (Dana)

DEFF Research Database (Denmark)

Nilsson, Birgitte; Jepsen, Per Meyer; Bucklin, Ann

2018-01-01

for these genes between 15 min and 24 h following exposure. Since handling stress clearly affects transcriptional patterns, it is important to consider handling when designing experiments, by either including additional controls or avoiding focus on impacted genes. Not considering handling in gene expression...... studies can lead to inaccurate conclusions. The present study provides a baseline for studying handling stress in future studies using this model organism and others....

Does predation control adult sex ratios and longevities in marine pelagic copepods?

DEFF Research Database (Denmark)

Hirst, A.G.; Bonnet, D.; Conway, D.V.P.

2010-01-01

We assess the causes of adult sex ratio skew in marine pelagic copepods by examining changes in these ratios between the juveniles and adults, sexual differences in juvenile stage durations, and mortality rates of adults in the field and laboratory (when free from predators). In the field, late...... copepodite stages (CIV and CV) commonly have sex ratios that are either not significantly different from equity (1 : 1), or slightly male biased. By contrast, in adults, these ratios are commonly significantly biased toward female dominance. Sex ratio skews are therefore primarily attributable to processes...... in adults. Members of the non-Diaptomoidea have especially skewed adult ratios; in the members Oithonidae and Clausocalanidae this is not generated from differences between male and female adult physiological longevity (i.e., laboratory longevity when free of predators). In the genera Acartia, Oithona...

Grazers and phytoplankton growth in the oceans: an experimental and evolutionary perspective.

Science.gov (United States)

Ratti, Simona; Knoll, Andrew H; Giordano, Mario

2013-01-01

The taxonomic composition of phytoplankton responsible for primary production on continental shelves has changed episodically through Earth history. Geological correlations suggest that major changes in phytoplankton composition correspond in time to changes in grazing and seawater chemistry. Testing hypotheses that arise from these correlations requires experimentation, and so we carried out a series of experiments in which selected phytoplankton species were grown in treatments that differed with respect to the presence or absence of grazers as well as seawater chemistry. Both protistan (Euplotes sp.) and microarthropod (Acartia tonsa) grazers changed the growth dynamics and biochemical composition of the green alga Tetraselmis suecica, the diatom Thalassiosira weissflogii, and the cyanobacterium Synechococcus sp., increasing the specific growth rate and palatability of the eukaryotic algae, while decreasing or leaving unchanged both parameters in the cyanobacteria. Synechococcus (especially) and Thalassiosira produced toxins effective against the copepod, but ciliate growth was unaffected. Acartia induced a 4-6 fold increase of Si cell quota in the diatom, but Euplotes had no similar effect. The differential growth responses of the eukaryotic algae and cyanobacteria to ciliate grazing may help to explain the apparently coeval radiation of eukaryophagic protists and rise of eukaryotes to ecological prominence as primary producers in Neoproterozoic oceans. The experimental results suggest that phytoplankton responses to the later radiation of microarthropod grazers were clade-specific, and included changes in growth dynamics, toxin synthesis, encystment, and (in diatoms) enhanced Si uptake.

Seasonality in the Mesozooplankton Community of Delaware Bay, USA

Science.gov (United States)

Wickline, A.; Cohen, J.

2016-02-01

Zooplankton communities in temperate estuaries undergo seasonal shifts in abundance and species composition, though the physical/biological mechanisms behind these shifts vary among systems. Delaware Bay is a well-mixed estuary on the mid-Atlantic coast with predictable seasonal variation in environmental conditions and circulation. To understand factors influencing mesozooplankton community dynamics in this system, we conducted seasonal sampling at 16 stations over the estuary's salinity range in 2014-2015. Sampling paralleled the last similar investigation into Delaware Bay zooplankton, conducted in the early 1950s. Biomass, measured as dry weight and totaled for all stations, was low in late summer and high in spring and fall. Bio-volume, measured either as displacement volume or calculated from ZooScan processing to exclude detritus, also showed a similar pattern. Across seasons, the mesozooplankton community was dominated by copepods, representing over 60% of the relative abundance at each station. Acartia tonsa was the dominant calanoid species in summer and fall, with abundances up to 7,353 ind. m-3, which is similar to the 1950s. In spring, Centropages hamatus and C. typicus were dominant at densities up to 2,550 ind. m-3 throughout the estuary, which is an increase from the 1950s. Environmental data suggest the seasonal shift in dominance from neritic Centropages to estuarine Acartia could be driven by increased stratification of the estuary during periods of high river discharge in spring, creating a two-layer system with a bottom advection current fed by the coastal ocean, bringing coastal species into the estuary. As river discharge decreases, the advection current is reduced, creating a well-mixed estuary and allowing Acartia to dominante. As river discharge is ultimately determined by precipitation, which is predicted to increase during winter with climate change in this region, the phenology of mesozooplankton species dynamics could shift as well.

Recommended feeding regime and light climate in live feed cultures of the calanoid copepod Acartia tonsa Dana

DEFF Research Database (Denmark)

Jepsen, Per Meyer; Steensbjerg Bjørbæk, Niels; Rayner, Thomas Allan

2017-01-01

(spiked feeding), in four equal pulses (pulsed feeding), and evenly over 24 h (continuous feeding). The feeding regimes were investigated at low food levels (~200 µg C L−1) and at full-saturated food levels (~1800 µg C L−1). As photoperiod may have an effect on feeding uptake and productivity, the present...

Effects of methyltestosterone, letrozole, triphenyltin and fenarimol on histology of reproductive organs of the copepod Acartia tonsa

DEFF Research Database (Denmark)

Watermann, Burkard T.; Albanis, Triantafyllos A.; Dagnac, Thierry

2013-01-01

and displayed deformations. In females, LET induced a disorder of oogenesis and disturbances in yolk synthesis. TPT stimulated the male reproductive system at 0.0014 and 0.0035μg TPT-SnL−1, whereas inhibiting effects were observed in the female gonad at 0.0088μg TPT-SnL−1. In FEN exposed females proliferation...... to act as androgens in vertebrates. The digestive tract, musculature, nervous system, reproductive organs, gonad and accessory sexual glands were examined by light microscopy after routine staining and immune-labelling for detection of apoptosis and determination of proliferation activities. MET induced...... of gametes was reduced and yolk formation showed irregular features at 2.8–105μgL−1. In FEN exposed males an elevated proliferation activity was observed. No pathological alterations in other organ systems, e.g. the digestive tract including the hindgut acting as respiratory organ, the nervous system...

A new species of Acartia (Copepoda, Calanoida) from Cochin Harbour, India, and adjacent areas

Digital Repository Service at National Institute of Oceanography (India)

Abraham, S.

During the course of a study of the family Acartiidae of Cochin harbour and its neighbourhood, a species of Acartia different from all other known species of Acartia, was found. Its characteristics, habitat and seasonal distribution form the theme...

Composition, abundance and distribution of macrozooplankton in Culebra Bay, Gulf of Papagayo, Pacific coast of Costa Rica and its value as bioindicator of pollution

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Melinda Bednarski

2004-12-01

Full Text Available The abundance, distribution and composition of the macrozooplankton of Culebra Bay, Costa Rica (10º 38’ N - 85º 40’ W were studied at four stations throughout the dry (February - May and rainy (September - November seasons of 2000. The samples were collected at two-week intervals using a 500µm mesh net with a 0.5 m diameter opening. Copepods (23-31% and ostracods (20-34% were predominant throughout the year, followed by cladocerans (2.5-14%, zoea (6.6-9.5%, and siphonophores (2.5-7.2%. High densities of zooplankton were obtained in February and March with peak abundance on March 18. The lowest densities were observed on September 3 and November 5. Significant differences in abundances at each station were observed for the groups Acartia tonsa (Copepoda, Ctenophora, Medusae, Ostracoda, Zoea, and Amphipoda. Comparison of the dry and rainy seasons revealed significantly higher zooplankton abundance in the dry season and copepod domination of all stations; during the rainy season ostracods dominated the off-shore areas. Zooplankton abundance and distribution are influenced by upwelling, which occurs during the dry season in Culebra BayLa abundancia, distribución y composición del macrozooplancton fue estudiada en bahía Culebra Costa Rica (10º 38’ N and 85º 40’ W en cuatro estaciones durante la época seca (Febrero-Mayo y lluviosa (Setiembre - Noviembre del año 2000. Las muestras fueron colectadas en intervalos de dos semanas usando una red de 500µm de poro y 0.50-m de diámetro. Copépodos (23-31% y ostrácodos (20-34% fueron predominantes através del año, seguidos por los cladóceros (2.5-14%, zoea (6.6-9.5%, y sifonóforos (2.5-7.2%. Altas densidades de zooplancton fueron obtenidas en Febrero y Marzo, con un pico el 18 de Marzo. Las más bajas densidades fueron observadas el 3 de Septiembre y 5 de Noviembre. Se observaron diferencias significativas en las abundancias en cada estación para los copépodos de la especie Acartia

Rapid reassessment of the eutrophication status of Kingston Harbour, Jamaica using the zooplankton community

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Patrice A. Francis

2014-09-01

Full Text Available Previous extensive studies of zooplankton distribution in the eutrophic Kingston Harbour established that it was being continuously contaminated. We assessed the community in 2011, 17 years after a previous study and five years after the introduction of a tertiary waste water system. Sampling was conducted for four weeks at eight stations identical to those sampled in a previous study. We used horizontal surface tows with a 200µm net. A total of 73 zooplankton taxa were identified and copepods dominated with 20 species. Mean total abundances were high, ranging from a minimum of 2 383 animals m-3 in the southern region of Hunts Bay to 194 166 animals m-3at the Inner Harbour. Five zooplankton taxa (Acartia tonsa, Paracalanus spp., Temora turbinata, Penilia avirostris and Lucifer faxoni that were previously identified as indicators, were again important in the Harbour. The overall zooplankton abundances were similar and in some cases higher than the previous study. There was no significant improvement in the water quality since the introduction of the treatment system at Soapberry. This may be a result of unknown nutrient inputs or of nutrient remaining in the sediments.

Combined toxicity effects of chlorine, ammonia, and temperature on marine plankton. Progress report, September 16, 1975--September 30, 1976

Energy Technology Data Exchange (ETDEWEB)

Goldman, J. C.; Ryther, J. H.

1976-10-01

Research on the combined effects of chlorine, ammmonia and temperature on marine plankton have been carried out for 20 months. To date continuous-flow bioassays have been conducted on lobster larvae (Homarus americanus), oyster larvae (Crassostrea virginica), copepods (Acartia tonsa), rotifers (Brachionus plicatilis), three juvenile and larval fish, killifish (Fundulus heteroclitus), scup (Stenotomus versicolor), and winter flounder (Pseudopleuronectes americanus), and phytoplankton (the diatom Phaeodactylum tricornutum). In addition, studies on zooplankton metabolism, filtration rates, and growth were carried out on exposed organisms. In general, the responses of invertebrates were distinctly different than those of fish: increasing mortality with increasing chlorine dose and greater sensitivity to chloramines than free chlorine in the former, and a threshold level of chlorine and greater sensitivity to free chlorine in the latter. Phytoplankton responses indicate that chlorine effects on primary producers are minimal compared to the serious effects on zooplankton, particularly larval forms that spawn intermittently. The overall conclusion of our studies is that chlorine application at power plants must be carried out with extreme caution and that serious consideration should be given to applying dechlorination at all coastal cooling systems.

Copepod response to ocean acidification in a low nutrient-low chlorophyll environment in the NW Mediterranean Sea

Science.gov (United States)

Zervoudaki, S.; Krasakopoulou, E.; Moutsopoulos, T.; Protopapa, M.; Marro, S.; Gazeau, F.

2017-02-01

In order to identify how ocean acidification will influence biological interactions and fluxes among planktonic organisms and across trophic levels, a large-scale mesocosm experiment was performed in the oligotrophic Northwestern Mediterranean Sea in the framework of the European MedSeA project. Nine mesocosms were deployed in the Bay of Calvi (Corsica, France) in summer 2012. Six mesocosms were subjected to different levels of CO2 partial pressures (pCO2; 550, 650, 750, 850, 1000 and 1250 μatm) covering the range of atmospheric pCO2 anticipated for the end of this century depending on future emission scenarios, and the last three mesocosms were unaltered (ambient pCO2 of ∼450 μatm). During this 21-day experiment, we monitored copepod egg and naupliar stocks, estimated copepod (Acartia clausi and Centropages typicus) feeding rates and determined the abundance and taxonomic composition of the mesozooplankton community at the start and at the completion of the experiment. This community was clearly dominated by copepods and its final composition slightly varied between mesocosms most likely due to natural and experimental variability that cannot be related to CO2 conditions. The abundances of eggs and nauplii as well as feeding rates of A. clausi and C. typicus on diatoms, dinoflagellates and ciliates showed no significant differences among CO2 levels. The above findings suggest that the experimental set-up especially for the specific trophic conditions and the short duration of the experiment did not provide the information on the effect of acidification that was expected. The acidification might have an effect on planktonic communities and even worsen the problems imposed by food limitation, therefore on this short time scale experiment and under the extreme ologotrophic conditions the signal that dominates was the food limitation.

Noctiluca and copepods grazing on the phytoplankton community in a nutrient-enriched coastal environment along the southwest coast of India.

Science.gov (United States)

Arunpandi, N; Jyothibabu, R; Jagadeesan, L; Gireeshkumar, T R; Karnan, C; Naqvi, S W A

2017-07-01

The relative grazing impact of Noctiluca scintillans (hereafter referred only Noctiluca) and copepods (Acrocalanus gracilis, Paracalanus parvus, Acartia danae and Oithona similis) on the phytoplankton community in an upwelling-mudbank environment along the southwest coast India is presented here. This study was carried out during the Pre-Southwest Monsoon (April-May) to the Late Southwest Monsoon (August) period in 2014. During the sampling period, large hydrographical transformation was evident in the study area (off Alappuzha, Southwest coast of India); warmer Pre-Southwest Monsoon water column condition got transformed into cooler and nitrate-rich hypoxic waters during the Southwest Monsoon (June-August) due to intense coastal upwelling. Copepods were present in the study area throughout the sampling period with a noticeable increase in their abundance during the Southwest Monsoon. On the other hand, the first appearance of Noctiluca in the sampling location was during the Early Southwest Monsoon (mid-June) and thereafter their abundance increased towards the Peak Southwest Monsoon. The grazing experiments carried out as per the food removal method showed noticeable differences in the feeding preferences of Noctiluca and copepods, especially on the different size fractions of phytoplankton. Noctiluca showed the highest positive electivity for the phytoplankton micro-fraction (av. 0.49 ± 0.04), followed by nano-fraction (av. 0.17 ± 0.04) and a negative electivity for the pico-fraction (av. -0.66 ± 0.06). In total ingestion of Noctiluca, micro-fraction contribution (83.7%) was significantly higher compared to the nano- (15.7%) and pico-fractions (0.58%). On the other hand, copepods showed the highest positive electivity for the phytoplankton nano-fraction (av. 0.38 ± 0.04) followed by micro- (av. -0.17 ± 0.05) and pico-fractions (av. -0.35 ± 0.05). Similarly, in total ingestion of copepods, nano-fraction (69.7%) was the highest followed by micro

Detecting in situ copepod diet diversity using molecular technique: development of a copepod/symbiotic ciliate-excluding eukaryote-inclusive PCR protocol.

Science.gov (United States)

Hu, Simin; Guo, Zhiling; Li, Tao; Carpenter, Edward J; Liu, Sheng; Lin, Senjie

2014-01-01

Knowledge of in situ copepod diet diversity is crucial for accurately describing pelagic food web structure but is challenging to achieve due to lack of an easily applicable methodology. To enable analysis with whole copepod-derived DNAs, we developed a copepod-excluding 18S rDNA-based PCR protocol. Although it is effective in depressing amplification of copepod 18S rDNA, its applicability to detect diverse eukaryotes in both mono- and mixed-species has not been demonstrated. Besides, the protocol suffers from the problem that sequences from symbiotic ciliates are overrepresented in the retrieved 18S rDNA libraries. In this study, we designed a blocking primer to make a combined primer set (copepod/symbiotic ciliate-excluding eukaryote-common: CEEC) to depress PCR amplification of symbiotic ciliate sequences while maximizing the range of eukaryotes amplified. We firstly examined the specificity and efficacy of CEEC by PCR-amplifying DNAs from 16 copepod species, 37 representative organisms that are potential prey of copepods and a natural microplankton sample, and then evaluated the efficiency in reconstructing diet composition by detecting the food of both lab-reared and field-collected copepods. Our results showed that the CEEC primer set can successfully amplify 18S rDNA from a wide range of isolated species and mixed-species samples while depressing amplification of that from copepod and targeted symbiotic ciliate, indicating the universality of CEEC in specifically detecting prey of copepods. All the predetermined food offered to copepods in the laboratory were successfully retrieved, suggesting that the CEEC-based protocol can accurately reconstruct the diets of copepods without interference of copepods and their associated ciliates present in the DNA samples. Our initial application to analyzing the food composition of field-collected copepods uncovered diverse prey species, including those currently known, and those that are unsuspected, as copepod prey

Molecular Characterization of Copepod Photoreception.

Science.gov (United States)

Porter, Megan L; Steck, Mireille; Roncalli, Vittoria; Lenz, Petra H

2017-08-01

Copepod crustaceans are an abundant and ecologically significant group whose basic biology is guided by numerous visually guided behaviors. These behaviors are driven by copepod eyes, including naupliar eyes and Gicklhorn's organs, which vary widely in structure and function among species. Yet little is known about the molecular aspects of copepod vision. In this study we present a general overview of the molecular aspects of copepod vision by identifying phototransduction genes from newly generated and publicly available RNA-sequencing data and assemblies from 12 taxonomically diverse copepod species. We identify a set of 10 expressed transcripts that serve as a set of target genes for future studies of copepod phototransduction. Our more detailed evolutionary analyses of the opsin gene responsible for forming visual pigments found that all of the copepod species investigated express two main groups of opsins: middle-wavelength-sensitive (MWS) opsins and pteropsins. Additionally, there is evidence from a few species (e.g., Calanus finmarchicus, Eurytemora affinis, Paracyclopina nana, and Lernaea cyprinacea) for the expression of two additional groups of opsins-the peropsins and rhodopsin 7 (Rh7) opsins-at low levels or distinct developmental stages. An ontogenetic analysis of opsin expression in Calanus finmarchicus found the expression of a single dominant MWS opsin, as well as evidence for differences in expression across development in some MWS, pteropsin, and Rh7 opsins, with expression peaking in early naupliar through early copepodite stages.

Feeding preference and daily ration of 12 dominant copepods on mono and mixed diets of phytoplankton, rotifers, and detritus in a tropical coastal water.

Science.gov (United States)

Jagadeesan, L; Jyothibabu, R; Arunpandi, N; Anjusha, A; Parthasarathi, S; Pandiyarajan, R S

2017-09-11

Results of the experimental studies on the feeding habit and daily ration (DR) of 12 dominant copepods from a tropical coastal water (off Kochi, Southwest coast of India) on different food items (phytoplankton, rotifers, and detritus) are presented. Even though, all species of copepods consumed all types of food items in the experiments, they showed noticeable feeding preferences, having important ecological implications. Calanoid Paracalanus parvus and Acrocalanus gracilis consumed phytoplankton and rotifers equally in mono diets (74-89% of DR) and mixed diets (53-82% of DR), which indicated their ability to shift their diet in natural environment based on the availability of food items. Calanoid Acartia erythraea and A. danae consumed more phytoplankton (DR 83 and 72%, respectively) than rotifers (DR 51 and 46%, respectively) in mono diets, and in mixed diets, their consumption was high in phytoplankton combined food mixtures (P + R DR and P + D DR) rather than the R + D food type, indicated their preference for mixed diets of phytoplankton. Similarly, Calanoid Temora turbinata, Pseudodiaptomus serricaudatus, and Centropages tenuiremis preferred a herbivorous diet as evidenced by their high ingestion rate on phytoplankton mono (70 to 87% to their DR) and mixed diets (58 to 80% of DR). On the other hand, Cyclopoid Oithona similis and Poecilostomatoid Corycaeus danae preferred a carnivorous diet, consuming more rotifers (> 80% of DR) than phytoplankton (18-20% of DR) and detritus (5-6% of DR). Harpacticoids Macrosetella gracilis and Euterpina acutifrons equally preferred phytoplankton (78-92% of DR) and detritus (65-89% of DR). The study showed that the dominant copepods in the coastal waters off Kochi occupy different trophic niches available in the environment, which may be applicable in other similar environments as well.

Observing copepods through a genomic lens

Directory of Open Access Journals (Sweden)

Johnson Stewart C

2011-09-01

Full Text Available Abstract Background Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to

Observing copepods through a genomic lens

Science.gov (United States)

2011-01-01

Background Copepods outnumber every other multicellular animal group. They are critical components of the world's freshwater and marine ecosystems, sensitive indicators of local and global climate change, key ecosystem service providers, parasites and predators of economically important aquatic animals and potential vectors of waterborne disease. Copepods sustain the world fisheries that nourish and support human populations. Although genomic tools have transformed many areas of biological and biomedical research, their power to elucidate aspects of the biology, behavior and ecology of copepods has only recently begun to be exploited. Discussion The extraordinary biological and ecological diversity of the subclass Copepoda provides both unique advantages for addressing key problems in aquatic systems and formidable challenges for developing a focused genomics strategy. This article provides an overview of genomic studies of copepods and discusses strategies for using genomics tools to address key questions at levels extending from individuals to ecosystems. Genomics can, for instance, help to decipher patterns of genome evolution such as those that occur during transitions from free living to symbiotic and parasitic lifestyles and can assist in the identification of genetic mechanisms and accompanying physiological changes associated with adaptation to new or physiologically challenging environments. The adaptive significance of the diversity in genome size and unique mechanisms of genome reorganization during development could similarly be explored. Genome-wide and EST studies of parasitic copepods of salmon and large EST studies of selected free-living copepods have demonstrated the potential utility of modern genomics approaches for the study of copepods and have generated resources such as EST libraries, shotgun genome sequences, BAC libraries, genome maps and inbred lines that will be invaluable in assisting further efforts to provide genomics tools for

Study on zooplankton distributions in Mahin Lagoon within ...

African Journals Online (AJOL)

Ciliophorans (such as Tintinnopsis, Codonellopsis spp) were distributed mostly within the stations close to the Atlantic Ocean with higher salinity while freshwater stations further upstream were prevailed mostly by rotifers (such as Ascomorpha, Brachionus, Keratella, Filinia spp.). Copepods (such as Acartia, Paracalanus, ...

Origin of resources and trophic pathways in a large SW Atlantic estuary: An evaluation using stable isotopes

Science.gov (United States)

Botto, Florencia; Gaitán, Esteban; Mianzan, Hermes; Acha, Marcelo; Giberto, Diego; Schiariti, Agustín; Iribarne, Oscar

2011-03-01

The Río de la Plata (34° 36' S, 55° 58' W; Argentina and Uruguay) estuary, one of the most important South American estuarine environments, is characterized by weak seasonal freshwater discharge, low tidal amplitude (freshwater marshes both contribute to the food web of the Río de la Plata estuary. On the basis of the sampled species, we identified four trophic levels. The clam Mactra isabelleana, the calanoid copepod Acartia tonsa, and the opossum shrimp Neomysis americana are the primary consumers. The rays Atlantoraja castelnaui and Squatina guggenheim and the shark Galeorhinus galeus are the top predators. The Río de la Plata food web shows an important input of nutrients derived from phytoplankton. Rays, sharks, and predatory gastropods reveal an important contribution of C4 plants (likely Spartina spp.). However, production derived from C3 plants is also important for some species. The fishes Brazilian menhaden, Brevoortia aurea; the stripped weakfish Cynoscion guatucupa; and the whitemouth croaker, Micropogonias furnieri, showed differences in their isotopic signatures as juveniles and adults, indicating different food sources, and they were therefore treated as different components of the food web. Our data suggest that detritus from salt and freshwater marshes is reaching the Río de la Plata estuary and can be an important allocthonous source of energy to this environment.

Occurrence of heavy copepod infestation on Hemiramphus lutkei and double parasitisms on Hemiramphus far with copepod (Lernaeenicus hemiramphi) and isopod (Mothocya plagulophora)

OpenAIRE

Vijayakumar, R.; Raja, K.; Velvizhi, S.; Sinduja, K.; Gopalakrishnan, A.

2013-01-01

In the present study about, 66 copepod parasites of Lernaeenicus hemiramphi of two Hemiramphus sp., H. far (17 copepod) and H. lutkei (49 copepod), and an isopod (Mothocya plagulophora) on the gill chamber were observed. H. lutkei was added as a new host for L. hemiramphi. The copepod infestation was almost on the ventral side of the hosts.

Variability in estuarine water temperature gradients and influence on ...

African Journals Online (AJOL)

Structure and variability of water temperature gradients and potential influence on distribution of two tropical zooplankters (the mysid Mesopodopsis africana and the copepod Acartia natalensis) and their temperate congenerics (M. wooldridgei and A. longipatella) was investigated over a 10-year period in the Mgazi Estuary, ...

Short-term variability on mesozooplankton community in a shallow mixed estuary (Bahía Blanca, Argentina): Influence of tidal cycles and local winds

Science.gov (United States)

Menéndez, María C.; Piccolo, María C.; Hoffmeyer, Mónica S.

2012-10-01

The short-term dynamics of zooplankton in coastal ecosystems are strongly influenced by physical processes such as tides, riverine runoff and winds. In this study, we investigated the short-term changes of the representative taxa within mesozooplankton in relation to the semidiurnal tidal cycles. Also, we evaluated the influence of local winds on this short-term variability. Sampling was carried out bimonthly from December 2004 to April 2006 in a fixed point located in the inner zone of the Bahía Blanca Estuary, Argentina. Mesozooplankton samples were taken by pumps during 14-h tidal cycles at 3-h intervals, from surface and bottom. Vertical profiles of temperature and salinity as well as water samples to determine suspended particulate matter were acquired at each sampling date. All data concerning winds were obtained from a meteorological station and water level was recorded with a tide gauge. Holoplankton dominated numerically on meroplankton and adventitious fraction. Concerning holoplanktonic abundance, the highest values were attained by the calanoid copepods Acartia tonsa and Eurytemora americana. Meroplankton occurred mainly as barnacle larvae while benthic harpacticoids and Corophium sp. dominated the adventitious component. Semidiurnal tide was the main influence on the A. tonsa variability. However, noticeable differences in the abundance pattern as function of wind intensity were detected. Meroplankton abundance did not show a clear variation along the tidal cycle. Distributional pattern of harpacticoids seemed to be mainly modulated by velocity asymmetries in the tidal currents, in the same way as suspended particulate matter. However, the Corophium sp. distribution indicated probable behavioural responses associated with tides. The obtained results show how variable the mesozooplankton community structure can be over short-term time scales in mesotidal temperate estuaries. This variability should be taken into account for any zooplankton monitoring

Mortality of marine planktonic copepods : global rates and patterns

DEFF Research Database (Denmark)

Hirst, A.G.; Kiørboe, Thomas

2002-01-01

Using life history theory we make predictions of mortality rates in marine epi-pelagic copepods from field estimates of adult fecundity, development times and adult sex ratios. Predicted mortality increases with temperature in both broadcast and sac spawning copepods, and declines with body weight...... in broadcast spawners, while mortality in sac spawners is invariant with body size. Although the magnitude of copepod mortality does lie close to the overall general pattern for pelagic animals, copepod mortality scaling is much weaker, implying that small copepods are avoiding some mortality agent....../s that other pelagic animals of a similar size do not, We compile direct in situ estimates of copepod mortality and compare these with our indirect predictions; we find the predictions generally match the field measurements well with respect to average rates and patterns. Finally, by comparing in situ adult...

Prey detection in a cruising copepod

DEFF Research Database (Denmark)

Kjellerup, Sanne; Kiørboe, Thomas

2012-01-01

. Yet, direct interception has been proposed to explain how rapidly cruising, blind copepods feed on non-motile phytoplankton prey. Here, we demonstrate a novel mechanism for prey detection in a cruising copepod, and describe how motile and non-motile prey are discovered by hydromechanical and tactile...

Grazer-induced chain lenght plasticity reduces grazing risk in a marine diatom

DEFF Research Database (Denmark)

Bergkvist, Johanna; Thor, Peter; Jakobsen, Hans Henrik

2012-01-01

. marinoi was exposed to chemical cues from caged A. tonsa without physical contact with the responding cells. The reductions in chain length significantly reduced copepod grazing; grazing rates on chains (four cells or more) were several times higher compared to that of single cells. This suggests...... that chain length plasticity is a means for S. marinoi to reduce copepod grazing. In contrast, chain length was not suppressed in cultures exposed to the microzooplankton grazer Gyrodinium dominans. Size-selective predation may have played a key role in the evolution of chain formation and chain length...... plasticity in diatoms...

Does copepods influence dusky grouper (Epinephelus marginatus early development?

Directory of Open Access Journals (Sweden)

Monica Mateus

2014-06-01

Full Text Available Good knowledge on the development of early life stages is essential for successful conservation programs of threatened fish species. Diet and rearing system affects early life survival and juvenile quality. Copepods are the natural food of fish larvae in the wild possessing high nutritional value, when compared with live feeds used in aquaculture (rotifers and artemia, and a wide range of size classes. Rearing systems with low water column disturbance and low larval densities enhanced the survival of fragile fish larvae. The aim of this work is to evaluate the effect of the introduction of copepods in the diet of early dusky grouper larvae reared in controlled mesocosm systems using larval development and juvenile quality as indicators. Two feeding protocols were tested, one composed only by rotifers (Brachionus plicatilis, brine shrimp (Artemia spp. and dry feed and the other supplemented with copepods (Paracartia grani from mouth opening (2 day after hatching - DAH to 8 DAH. Feeding behavior, growth, survival, skeletal malformations and digestive enzymes activity was assessed at different developmental stages. The addition of copepods to the early larvae diet of dusky grouper resulted in faster development and higher survival rates. Larvae fed with copepods improved their development. At 20 DAH all larvae reared at the mesocosm with copedods were already at the stage of post-flexion while in the system without copepods this stage was attained later. At 25 DAH only 64% of the larvae were in post flexion in the mesoscosm without copepods. At 30 DAH larvae supplemented with copepods attained an acidic digestion (high specific activity of pepsin earlier than at the system without copepods. In this last system alkaline digestion (trypsin specific activity, characteristic of early larval stages, was significantly higher reinforcing the faster development of larvae fed with copepods. In both systems the incidence of skeletal malformations was low.

Copepods of the nearshore waters of Bombay

Digital Repository Service at National Institute of Oceanography (India)

Gajbhiye, S.N.; Stephen, R.; Nair, V.R.; Desai, B.N.

Variability in copepod population was studied along 2 transects off Mahim and Versova (Bombay, Maharashtra, India) during November 1979 to December 1980 covering eight stations from the creek towards the offshore area. Contribution of copepods...

Computational analysis and functional expression of ancestral copepod luciferase.

Science.gov (United States)

Takenaka, Yasuhiro; Noda-Ogura, Akiko; Imanishi, Tadashi; Yamaguchi, Atsushi; Gojobori, Takashi; Shigeri, Yasushi

2013-10-10

We recently reported the cDNA sequences of 11 copepod luciferases from the superfamily Augaptiloidea in the order Calanoida. They were classified into two groups, Metridinidae and Heterorhabdidae/Lucicutiidae families, by phylogenetic analyses. To elucidate the evolutionary processes, we have now further isolated 12 copepod luciferases from Augaptiloidea species (Metridia asymmetrica, Metridia curticauda, Pleuromamma scutullata, Pleuromamma xiphias, Lucicutia ovaliformis and Heterorhabdus tanneri). Codon-based synonymous/nonsynonymous tests of positive selection for 25 identified copepod luciferases suggested that positive Darwinian selection operated in the evolution of Heterorhabdidae luciferases, whereas two types of Metridinidae luciferases had diversified via neutral mechanism. By in silico analysis of the decoded amino acid sequences of 25 copepod luciferases, we inferred two protein sequences as ancestral copepod luciferases. They were expressed in HEK293 cells where they exhibited notable luciferase activity both in intracellular lysates and cultured media, indicating that the luciferase activity was established before evolutionary diversification of these copepod species. © 2013.

Optimal mate choice patterns in pelagic copepods

DEFF Research Database (Denmark)

Heuschele, Jan; Eliassen, Sigrun; Kiørboe, Thomas

2013-01-01

The importance of sexual selection for the evolution, dynamics and adaptation of organisms is well known for many species. However, the topic is rarely studied in marine plankton, the basis of the marine food web. Copepods show behaviors that suggest the existence of sexually selected traits......, and recent laboratory experiments identified some selected morphological traits. Here, we use a ‘life history-based’ model of sex roles to determine the optimal choosiness behavior of male and female copepods for important copepod traits. Copepod females are predicted to be choosy at population densities...... typically occurring during the main breeding season, whereas males are not. The main drivers of this pattern are population density and the difference in non-receptive periods between males and females. This suggests that male reproductive traits have evolved mainly due to mate competition. The model can...

The chemical ecology of copepods

DEFF Research Database (Denmark)

Heuschele, Jan; Selander, Erik

2014-01-01

for the functioning of the marine food web, much is still unknown. We synthesize current knowledge about chemical ecology of copepods including foraging, survival and reproduction. We also compile information on the sensory apparatus and new analytical approaches that may facilitate the identification of signal...... molecules. The review illustrates the importance of chemical interactions in many aspects of copepod ecology and identifies gaps in our knowledge, such as the lack of identified infochemicals and electrophysiological studies to confirm the function of sensory structures. We suggest approaches...

Functional & phylogenetic diversity of copepod communities

Science.gov (United States)

Benedetti, F.; Ayata, S. D.; Blanco-Bercial, L.; Cornils, A.; Guilhaumon, F.

2016-02-01

The diversity of natural communities is classically estimated through species identification (taxonomic diversity) but can also be estimated from the ecological functions performed by the species (functional diversity), or from the phylogenetic relationships among them (phylogenetic diversity). Estimating functional diversity requires the definition of specific functional traits, i.e., phenotypic characteristics that impact fitness and are relevant to ecosystem functioning. Estimating phylogenetic diversity requires the description of phylogenetic relationships, for instance by using molecular tools. In the present study, we focused on the functional and phylogenetic diversity of copepod surface communities in the Mediterranean Sea. First, we implemented a specific trait database for the most commonly-sampled and abundant copepod species of the Mediterranean Sea. Our database includes 191 species, described by seven traits encompassing diverse ecological functions: minimal and maximal body length, trophic group, feeding type, spawning strategy, diel vertical migration and vertical habitat. Clustering analysis in the functional trait space revealed that Mediterranean copepods can be gathered into groups that have different ecological roles. Second, we reconstructed a phylogenetic tree using the available sequences of 18S rRNA. Our tree included 154 of the analyzed Mediterranean copepod species. We used these two datasets to describe the functional and phylogenetic diversity of copepod surface communities in the Mediterranean Sea. The replacement component (turn-over) and the species richness difference component (nestedness) of the beta diversity indices were identified. Finally, by comparing various and complementary aspects of plankton diversity (taxonomic, functional, and phylogenetic diversity) we were able to gain a better understanding of the relationships among the zooplankton community, biodiversity, ecosystem function, and environmental forcing.

Does copepod size determine food consumption of particulate feeding fish?

DEFF Research Database (Denmark)

Deurs, Mikael van; Koski, Marja; Rindorf, Anna

2014-01-01

on adult particulate feeding fish is unknown. In the present study, we investigated the hypothesis that the availability of the large copepods determines food consumption and growth conditions of lesser sandeel (Ammodytes marinus) in the North Sea. Analysis of stomach content suggested that food...... consumption is higher for fish feeding on large copepods, and additional calculations revealed how handling time limitation may provide part of the explanation for this relationship. Comparing stomach data and zooplankton samples indicated that lesser sandeel actively target large copepods when......The climate-induced reduction in the mean copepod size, mainly driven by a decrease in the abundance of the large Calanus finmarchicus around 1987, has been linked to the low survival of fish larvae in the North Sea. However, to what extent this sort of reduction in copepod size has any influence...

Do copepods inhabit hypersaline waters worldwide? A short review and discussion

Science.gov (United States)

Anufriieva, Elena V.

2015-11-01

A small number of copepod species have adapted to an existence in the extreme habitat of hypersaline water. 13 copepod species have been recorded in the hypersaline waters of Crimea (the largest peninsula in the Black Sea with over 50 hypersaline lakes). Summarizing our own and literature data, the author concludes that the Crimean extreme environment is not an exception: copepod species dwell in hypersaline waters worldwide. There are at least 26 copepod species around the world living at salinity above 100; among them 12 species are found at salinity higher than 200. In the Crimea Cletocamptus retrogressus is found at salinity 360×10-3 (with a density of 1 320 individuals/m3) and Arctodiaptomus salinus at salinity 300×10-3 (with a density of 343 individuals/m3). Those species are probably the most halotolerant copepod species in the world. High halotolerance of osmoconforming copepods may be explained by exoosmolyte consumption, mainly with food. High tolerance to many factors in adults, availability of resting stages, and an opportunity of long-distance transportation of resting stages by birds and/or winds are responsible for the wide geographic distribution of these halophilic copepods.

Copepod guts as biogeochemical hotspots in the sea

DEFF Research Database (Denmark)

Tang, Kam W.; Glud, Ronnie N.; Glud, Anni

2011-01-01

The environmental conditions inside the gut of Calanus hyperboreus and C. glacialis were measured with microelectrodes. An acidic potential hydrogen (pH) gradient was present in the gut of C. hyperboreus, and the lowest pH recorded was 5.40. The gut pH of a starved copepod decreased by 0.53 after...... the copepod resumed feeding for a few hours, indicating the secretion of acidic digestive fluid. A copepod feeding on Thalassiosira weissflogii (diatom) had slightly lower pH than that feeding on Rhodomonas salina (cryptophyte). Oxygen was undersaturated in the gut of both C. hyperboreus and C. glacialis......, with a steep gradient from the anal opening to the metasome region. The central metasome region was completely anoxic. Food remains in the gut led to a lower oxygen level, and a diatom diet induced a stronger oxygen gradient than a cryptophyte diet. The acidic and suboxic–anoxic environments of the copepod gut...

The fluid dynamics of swimming by jumping in copepods

DEFF Research Database (Denmark)

Jiang, Houshuo; Kiørboe, Thomas

2011-01-01

Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic...... limited and temporally ephemeral owing to jump-impulsiveness and viscous decay. In contrast, continuous steady swimming generates two well-extended long-lasting momentum jets both in front of and behind the swimmer, as suggested by the well-known steady stresslet model. Based on the observed jump-swimming...... kinematics of a small copepod Oithona davisae, we further showed that jump-swimming produces a hydrodynamic disturbance with much smaller spatial extension and shorter temporal duration than that produced by a same-size copepod cruising steadily at the same average translating velocity. Hence, small copepods...

Prey perception in feeding-current feeding copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Goncalves, Rodrigo J.; Florian Couespel, Damien

2016-01-01

We reply to the comments of Paffenhöfer and Jiang () who argues that remote chemical prey perception is necessary for feeding-current feeding copepods to fulfill their nutritional requirements in a dilute ocean, that remote chemical prey detection may only be observed at very low prey concentrati......We reply to the comments of Paffenhöfer and Jiang () who argues that remote chemical prey perception is necessary for feeding-current feeding copepods to fulfill their nutritional requirements in a dilute ocean, that remote chemical prey detection may only be observed at very low prey...... cells have short intense leakage burst, only a very small fraction of prey cells would be available to the copepod at any instance in time and, thus would be inefficient at low prey concentration. Finally, we report a few new observations of prey capture in two species of copepods, Temora longicornis...... and Centropages hamatus, offered a 45-μm sized dinoflagellate at very low concentration. The observed short prey detection distances, up to a few prey cell radii, are consistent with mechanoreception and we argue briefly that near-field mechanoreception is the most likely and common prey perception mechanism...

Giant liposomes as delivery system for ecophysiological studies in copepods.

Science.gov (United States)

Buttino, Isabella; De Rosa, Giuseppe; Carotenuto, Ylenia; Ianora, Adrianna; Fontana, Angelo; Quaglia, Fabiana; La Rotonda, Maria Immacolata; Miralto, Antonio

2006-03-01

Giant liposomes are proposed as a potential delivery system in marine copepods, the dominant constituent of the zooplankton. Liposomes were prepared in the same size range as the food ingested by copepods (mean diameter of about 7 microm). The encapsulation of a hydrophilic and high molecular mass fluorescent compound, fluorescein isothiocyanate-dextran (FitcDx), within the liposomes provided a means of verifying copepod ingestion when viewed with the confocal laser-scanning microscope. Females of the calanoid copepod Temora stylifera were fed with FitcDx-encapsulated liposomes alone or mixed with the dinoflagellate alga Prorocentrum minimum. Control copepods were incubated with the P. minimum diet alone. Egg production rates, percentage egg-hatching success and number of faecal pellets produced were evaluated after 24 h and 48 h of feeding. Epifluorescence of copepod gut and faecal pellets indicated that the liposomes were actively ingested by T. stylifera in both experimental food conditions, with or without the dinoflagellate diet. Ingestion rates calculated using 3H-labelled liposomes indicated that females ingested more liposomes when P. minimum was added to the solution (16% vs 7.6% of uptake). When liposomes were supplied together with the algal diet, egg production rate, egg-hatching success and faecal pellet production were as high as those observed for the control diet. By contrary, egg production and hatching success were very low with a diet of liposomes alone and faecal pellet production was similar to that recorded in starved females. This results suggest that liposomes alone did not add any nutritive value to the diet, making them a good candidate as inert carriers to study the nutrient requirements or biological activity of different compounds. In particular, such liposomes are proposed as carriers for diatom-derived polyunsaturated aldehydes, which are known to impair copepod embryo viability. Other potential applications of liposomes as a delivery

Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia

KAUST Repository

Mojib, Nazia; Amad, Maan H.; Thimma, Manjula; Aldanondo, Naroa; Kumaran, Mande; Irigoien, Xabier

2014-01-01

The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid–protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin–protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton.

Carotenoid metabolic profiling and transcriptome-genome mining reveal functional equivalence among blue-pigmented copepods and appendicularia

KAUST Repository

Mojib, Nazia

2014-06-01

The tropical oligotrophic oceanic areas are characterized by high water transparency and annual solar radiation. Under these conditions, a large number of phylogenetically diverse mesozooplankton species living in the surface waters (neuston) are found to be blue pigmented. In the present study, we focused on understanding the metabolic and genetic basis of the observed blue phenotype functional equivalence between the blue-pigmented organisms from the phylum Arthropoda, subclass Copepoda (Acartia fossae) and the phylum Chordata, class Appendicularia (Oikopleura dioica) in the Red Sea. Previous studies have shown that carotenoid–protein complexes are responsible for blue coloration in crustaceans. Therefore, we performed carotenoid metabolic profiling using both targeted and nontargeted (high-resolution mass spectrometry) approaches in four different blue-pigmented genera of copepods and one blue-pigmented species of appendicularia. Astaxanthin was found to be the principal carotenoid in all the species. The pathway analysis showed that all the species can synthesize astaxanthin from β-carotene, ingested from dietary sources, via 3-hydroxyechinenone, canthaxanthin, zeaxanthin, adonirubin or adonixanthin. Further, using de novo assembled transcriptome of blue A. fossae (subclass Copepoda), we identified highly expressed homologous β-carotene hydroxylase enzymes and putative carotenoid-binding proteins responsible for astaxanthin formation and the blue phenotype. In blue O. dioica (class Appendicularia), corresponding putative genes were identified from the reference genome. Collectively, our data provide molecular evidences for the bioconversion and accumulation of blue astaxanthin–protein complexes underpinning the observed ecological functional equivalence and adaptive convergence among neustonic mesozooplankton.

What makes pelagic copepods so successful?

DEFF Research Database (Denmark)

Kiørboe, Thomas

2011-01-01

in detecting and escaping predators. The specific force production and velocities during escape jumps are both about an order of magnitude higher than for other similarly sized organisms. (ii) The capability to remotely detect prey and to either capture these as they arrive in a scanning current......, or as they swim through the perceptive sphere of the copepod, releases the copepods from the penalties associated filtering sticky water for prey particles. Scanning currents and active attack jumps are found in only few other zooplankters. (iii) Efficient mate finding in a mate-dilute environment allows...

Zooplankton motile behavior: traits and trade-offs in planktonic copepods

DEFF Research Database (Denmark)

van Someren Gréve, Hans

Research on planktonic copepod ecology is vital to understand the factors controlling marine food web dynamics since copepods are the major components of zooplankton communities and the main link between trophic levels in marine environments. Despite their taxonomic diversity, copepods share...... certain phenotypic characteristics, or ´traits´, that are essential in determining trophic interactions and fitness. One important characteristic that decisively influences organism interactions is behavior. Copepods display two distinct behavioral strategies in terms of motility: ´active´ (feeding...... differences between genders in feeding efficiency and predation risk. Finally, we also found that foraging activity decreased with increasing food availability, especially in active feeding strategies, resulting in a decrease in predation risk. Therefore, changes in behavior depending on food availability...

Freshwater copepods and rotifers: predators and their prey

Czech Academy of Sciences Publication Activity Database

Brandl, Zdeněk

2005-01-01

Roč. 546, č. 1 (2005), s. 475-489 ISSN 0018-8158. [Rotifera /10./. Illmitz, 07.06.2003-13.06.2003] R&D Projects: GA AV ČR(CZ) KSK6005114 Institutional research plan: CEZ:AV0Z60170517 Keywords : rotifers * cyclopoid copepod s * calanoid copepod s * feeding * predation Subject RIV: EG - Zoology Impact factor: 0.978, year: 2005

Re-assessing copepod growth using the Moult Rate method

DEFF Research Database (Denmark)

Hirst, Andrew G.; Keister, J. E.; Richardson, A. J.

2014-01-01

Estimating growth and production rates of mesozooplankton, and copepods in particular, is important in describing flows of material and energy though pelagic systems. Over the past 30 years, the Moult Rate (MR) method has been used to estimate juvenile copepod growth rates in ∼40 papers. Yet the MR......-moulting stage, e.g. copepodite stage 5 to adult. We performed experiments with Calanus pacificus to estimate growth of stage C5 using an alternative method. We found that the error size and sign varied between mass type (i.e. DW, C and N). Recommendations for practical future assessments of growth in copepods...

Trophic interactions and productivity of copepods as live feed from tropical Taiwanese outdoor aquaculture ponds

DEFF Research Database (Denmark)

Blanda, Elisa; Drillet, Guillaume; Huang, Cheng-Chien

2015-01-01

The present study describes three outdoor ponds for mass rearing of copepods in tropical southern Taiwan. The systems are designed for culturing and harvesting of copepods, which are used as live feed in the production of groupers in the region. However, the production of the most common copepod...... to enable a correct description of the copepods ecology and a preliminary evaluation of the status of the pond management; and (III) provide advices for improved management leading towards a higher and more stable output of P. annandalei. Copepods were experiencing prey ad libitum since the quantity...... during high season. This harvest, in terms of biomass, corresponded to 20–40% of the copepod standing stock, which indicates a sustainable management when compared to the secondary productivity of the copepods. To further increase the copepod production of the ponds, better water quality must be achieved...

Bioaccumulation and trophic transfer of dioxins in marine copepods and fish

International Nuclear Information System (INIS)

Zhang Qiong; Yang Liuyan; Wang Wenxiong

2011-01-01

Despite the great concerns about dioxins in the marine environments, the biokinetics and bioaccumulation of these compounds in marine organisms remains little known. Using radioactive tracers the aqueous uptake, dietary assimilation efficiency, and elimination of dioxins were measured in marine phytoplankton, copepods and seabream. The calculated uptake rate constant of dioxins decreased with increasing trophic levels, whereas the dietary assimilation efficiency (AE) was 28.5-57.6% in the copepods and 36.6-70.2% in the fish. The dietary AE was highly dependent on the food concentrations and food type. The elimination rate constant of dioxin in the copepods varied with different exposure pathways as well as food concentration and food type. Biokinetic calculation showed that dietary accumulation was the predominant pathway for dioxin accumulation in marine copepods and fish. Aqueous uptake can be an important pathway only when the bioconcentration of dioxins in the phytoplankton was low. - Highlights: → Radiotracer was used to quantify the biokinetics of dioxins in a marine food chain. → Aqueous uptake rate of dioxins decreased with increasing trophic levels. → Dietary assimilation efficiencies were comparable between the copepods and the fish. → Both food type and density significantly affected the dietary assimilation of dioxins. → Diet was the predominant pathway for dioxin accumulation in marine copepods and fish. - Biokinetic calculation showed that dietary accumulation was the predominant pathway for dioxin accumulation in marine copepods and fish.

Copepod behavior response to Burgers' vortex treatments mimicking turbulent eddies

Science.gov (United States)

Elmi, D.; Webster, D. R.; Fields, D. M.

2017-11-01

Copepods detect hydrodynamic cues in the water by their mechanosensory setae. We expect that copepods sense the flow structure of turbulent eddies in order to evoke behavioral responses that lead to population-scale distribution patterns. In this study, the copepods' response to the Burgers' vortex is examined. The Burgers' vortex is a steady-state solution of three-dimensional Navier-Stokes equations that allows us to mimic turbulent vortices at the appropriate scale and eliminate the stochastic nature of turbulence. We generate vortices in the laboratory oriented in the horizontal and vertical directions each with four intensity levels. The objective of including vortex orientation as a parameter in the study is to quantify directional responses that lead to vertical population distribution patterns. The four intensity levels correspond to target vortex characteristics of eddies corresponding to the typical dissipative vortices in isotropic turbulence with mean turbulent dissipation rates in the range of 0.002 to 0.25 cm2/s3. These vortices mimic the characteristics of eddies that copepods most likely encounter in coastal zones. We hypothesize that the response of copepods to hydrodynamic features depends on their sensory architecture and relative orientation with respect to gravity. Tomo-PIV is used to quantify the vortex circulation and axial strain rate for each vortex treatment. Three-dimensional trajectories of the copepod species Calanus finmarchicus are analyzed to examine their swimming kinematics in and around the vortex to quantify the hydrodynamic cues that trigger their behavior.

Gender-specific feeding rates in planktonic copepods with different feeding behavior

DEFF Research Database (Denmark)

van Someren Gréve, Hans; Almeda, Rodrigo; Lindegren, Martin

2017-01-01

Planktonic copepods have sexually dimorphic behaviors, which can cause differences in feeding efficiency between genders. Copepod feeding rates have been studied extensively but most studies have focused only on females. In this study, we experimentally quantified feeding rates of males and females...... copepods, particularly in ambush feeders, where the males must sacrifice feeding for mate searching. We conducted gender-specific functional feeding response experiments using prey of different size and motility. In most cases, gender-specific maximum ingestion and clearance rates were largely explained...... in copepods with different feeding behavior: ambush feeding (Oithona nana), feeding-current feeding (Temora longicornis) and cruising feeding (Centropages hamatus). We hypothesize that carbon-specific maximum ingestion rates are similar between genders, but that maximum clearance rates are lower for male...

Copepods use chemical trails to find sinking marine snow aggregates

DEFF Research Database (Denmark)

Lombard, Fabien; Koski, Marja; Kiørboe, Thomas

2013-01-01

Copepods are major consumers of sinking marine particles and hence reduce the efficiency of the biological carbon pump. Their high abundance on marine snow suggests that they can detect sinking particles remotely. By means of laboratory observations, we show that the copepod Temora longicornis ca...

Tumour-like anomaly of copepods-an evaluation of the possible causes in Indian marine waters.

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Jagadeesan, L; Jyothibabu, R

2016-04-01

Globally, tumour-like anomalies (TLA) in copepods and the critical assessment of their possible causes are rare. The exact causative factor and ecological consequences of TLA in copepods are still unclear and there is no quantitative data available so far to prove conclusively the mechanism involved in developing TLA in copepods. TLA in copepods are considered as a potential threat to the well-being of the aquatic food web, which prompted us to assess these abnormalities in Indian marine waters and assess the possible etiological agents. We carried out a focused study on copepods collected from 10 estuarine inlets and five coastal waters of India using a FlowCAM, advanced microscopes and laboratory-incubated observations. The analysis confirmed the presence of TLA in copepods with varying percentage of incidence in different environments. TLA was recorded in 24 species of copepods, which constituted ~1-15 % of the community in different environments. TLA was encountered more frequently in dominant copepods and exhibited diverse morphology; ~60 % was round, dark and granular, whereas ~20 % was round/oval, transparent and non-granular. TLA was mostly found in the dorsal and lateral regions of the prosome of copepods. The three suggested reasons/assumptions about the causes of TLA such as ecto-parasitism (Ellobiopsis infection), endo-parasitism (Blastodinium infection) and epibiont infections (Zoothamnium and Acineta) were assessed in the present study. We did find infections of endo-parasite Blastodinium, ecto-parasite Ellobiopsis and epibiont Zoothamnium and Acineta in copepods, but these infectious percentages were found <1.5 % to the total density and most of them are species specific. Detailed microscopical observations of the samples collected and the results of the incubation experiments of infected copepods revealed that ecto-parasitism, endo-parasitism and epibiont infections have less relevance to the formation of TLA in copepods. On the other hand

Copepod communities from surface and ground waters in the everglades, south Florida

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Bruno, M.C.; Cunningham, K.J.; Perry, S.A.

2003-01-01

We studied species composition and individual abundance of copepods in the surficial aquifer northeast of Everglades National Park. We identified the spatial distribution of subsurface habitats by assessing the depth of the high porosity layers in the limestone along a canal system, and we used copepods to assess the exchange between surface water and ground water along canal banks, at levels in the wells where high porosity connections to the canals exist. Surface- and ground-water taxa were defined, and species composition was related to areal position, sampling depth, and time. Subsurface copepod communities were dominated by surface copepods that disperse into the aquifer following the groundwater seepage along canal L-31N. The similarities in species composition between wells along canal reaches, suggest that copepods mainly enter ground water horizontally along canals via active and passive dispersal. Thus, the copepod populations indicate continuous connections between surface- and ground waters. The most abundant species were Orthocyclops modestus, Arctodiaptomus floridanus, Mesocyclops edax, and Thermocyclops parvus, all known in literature from surface habitats; however, these species have been collected in ground water in ENP. Only two stygophiles were collected: Diacylcops nearcticus and Diacyclops crassicaudis brachycercus. Restoration of the Everglades ecosystem requires a mosaic of data to reveal a complete picture of this complex system. The use of copepods as indicators of seepage could be a tool in helping to assess the direction and the duration of surface and ground water exchange.

Seasonal variation in the copepod gut microbiome in the subtropical North Atlantic Ocean.

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Shoemaker, Katyanne M; Moisander, Pia H

2017-08-01

Characterisation of marine copepod gut microbiome composition and its variability provides information on function of marine food webs, biogeochemical cycles and copepod health. Copepod gut microbiomes were investigated quarterly over two years at the Bermuda Atlantic Time-series Station in the North Atlantic Subtropical Gyre, while assessing seasonal shifts in stable and transient communities. Microbial communities were analysed using amplicon sequencing targeting the bacterial 16S rRNA V3-V4 region and the cyanobacterial ntcA gene. Persistent bacterial groups belonging to Firmicutes, Bacteroidetes and Actinobacteria were present in the copepod guts throughout the year, and showed synchronous changes, suggesting a link to variability in copepod nutritional content. The gut communities were separate from those in the seawater, suggesting the copepod gut hosts long-term, specialized communities. Major temporal variations in the gut communities during the early winter and spring, specifically a high relative abundance of Synechococcus (up to 65%), were attributed to bacterioplankton shifts in the water column, and copepod grazing on these picoplanktonic cyanobacteria. The presence of obligate and facultative anaerobes, including Clostridiales year round, suggests that anaerobic bacterial processes are common in these dynamic microhabitats in the oligotrophic open ocean. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Developmental Stages of some Tropical and Subtropical Planktonic Marine Copepods

NARCIS (Netherlands)

Björnberg, Tagea K.S.

1972-01-01

Most planktonic marine copepods have nauplii which differ greatly from the copepodids so that it is difficult to relate them to the adult form. Rearing experiments are usually unsuccessful; only 8% of ca. 800 species of planktonic marine copepods have identified nauplii (see below cited list). To

A global synthesis of seasonal temperature-size responses in copepods

DEFF Research Database (Denmark)

Horne, Curtis R.; Hirst, Andrew G.; Atkinson, David

2016-01-01

is that calanoid copepods, which utilize feeding currents to capture prey, exhibit a four-fold greater reduction in adult body mass per degrees C (-3.66%) compared with cyclopoid copepods (-0.91%), which are ambush feeders. By contrast, species body size or reproductive strategy did not explain variation...

Propulsion efficiency and imposed flow fields of a copepod jump.

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Jiang, Houshuo; Kiørboe, Thomas

2011-02-01

Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed the imposed flow fields and associated energetics of jumps by means of computational fluid dynamics simulations by modeling the copepod as a self-propelled body. The computational fluid dynamics simulation was validated by particle image velocimetry data. The flow field generated by a repositioning jump quickly evolves into two counter-rotating viscous vortex rings that are near mirror image of one another, one in the wake and one around the body of the copepod; this near symmetrical flow may provide hydrodynamic camouflage because it contains no information about the position of the copepod prey within the flow structure. The flow field associated with an escape jump sequence also includes two dominant vortex structures: one leading wake vortex generated as a result of the first jump and one around the body, but between these two vortex structures is an elongated, long-lasting flow trail with flow velocity vectors pointing towards the copepod; such a flow field may inform the predator of the whereabouts of the escaping copepod prey. High Froude propulsion efficiency (0.94-0.98) was obtained for individual power stroke durations of all simulated jumps. This is unusual for small aquatic organisms but is caused by the rapidity and impulsiveness of the jump that allows only a low-cost viscous wake vortex to travel backwards.

Physiological improvement in the copepod Eurytemora affinis through thermal and multi-generational selection

DEFF Research Database (Denmark)

Souissi, Anissa; Souissi, Sami; Hansen, Benni Winding

2016-01-01

As a major part of fish larval diet in nature, copepods constitute an appropriate live prey for aquaculture purposes. Considering the difficulty of mastering copepod mass production, studies on their growth performance at different environmental conditions are needed to improve their productivity....... In this study a new selective approach based on temperature control is proposed to improve the physiological (body size, fecundity and lipid storage) performance of copepods. The estuarine copepod Eurytemora affinis known to have a high genetic variance in temperature tolerance was used as a biological model....... First two different copepod lines were obtained after long-term culture at constant cold (7°C) and warm (20°C) temperatures. Then both populations were transferred to a higher temperature of 24°C appropriate for aquaculture use and followed during five generations. During the first two generations (F1–F...

Vibrio elicits targeted transcriptional responses from copepod hosts.

Science.gov (United States)

Almada, Amalia A; Tarrant, Ann M

2016-06-01

Copepods are abundant crustaceans that harbor diverse bacterial communities, yet the nature of their interactions with microbiota are poorly understood. Here, we report that Vibrio elicits targeted transcriptional responses in the estuarine copepod Eurytemora affinis We pre-treated E. affinis with an antibiotic cocktail and exposed them to either a zooplankton specialist (Vibrio sp. F10 9ZB36) or a free-living species (Vibrio ordalii 12B09) for 24 h. We then identified via RNA-Seq a total of 78 genes that were differentially expressed following Vibrio exposure, including homologs of C-type lectins, chitin-binding proteins and saposins. The response differed between the two Vibrio treatments, with the greatest changes elicited upon inoculation with V. sp. F10 We suggest that these differentially regulated genes play important roles in cuticle integrity, the innate immune response, and general stress response, and that their expression may enable E. affinis to recognize and regulate symbiotic vibrios. We further report that V. sp. F10 culturability is specifically altered upon colonization of E. affinis These findings suggest that rather than acting as passive environmental vectors, copepods discriminately interact with vibrios, which may ultimately impact the abundance and activity of copepod-associated bacteria. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hydrodynamics and energetics of jumping copepod nauplii and copepodids

DEFF Research Database (Denmark)

Wadhwa, Navish; Andersen, Anders Peter; Kiørboe, Thomas

2014-01-01

Within its life cycle, a copepod goes through drastic changes in size, shape and swimming mode. In particular, there is a stark difference between the early (nauplius) and later (copepodid) stages. Copepods inhabit an intermediate Reynolds number regime (between similar to 1 and 100) where both v......, presumably due to the change in hydrodynamic regime accompanied with a well-adapted body form and swimming stroke...

Diversity of

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Mohamed M. Abou Zaid

2014-01-01

Full Text Available Seasonal abundance, biomass, and taxonomic composition of copepods in El-Mex Bay (Southeastern Mediterranean region were studied from autumn 2011 to 2012. Most species within the copepod communities displayed a clear pattern of succession throughout the investigation period. Generally copepods were the predominant group. They contributed numerically 57% of the total zooplankton counts with an average of 5083 organisms/m3 and a total number of 203,333 individuals. The bay harbored 50 species belonging to 28 genera within 19 families and 4 orders under one class. Calanoids were represented by 24 species which formed 31.6% of total copepods predominantly Acartia clausi, Calocalanus pavo, Clausocalanus furcatus, Eucalanus crassus, Nannocalanus minor, Paracalanus parvus, Eucalanus subcrassus, and Temora longicornis. Cyclopoids comprised 13 species of which Acanthocyclops americanus, Halicyclops magniceps, Oithona attenuata, and Oithona nana were the most abundant adult copepods. Eleven Harpacticoid species were also recorded with Euterpina acutifrons, Microsetella norvegica, Onychocamptus mohammed being the most prevalent. It was found however, that two Poecilostomatoida species were rarely encountered in the plankton Oncaea minuta and Corycaeus typicus. Copepod larvae and copepodite stages formed the main bulk of copepod Fauna as noticed in the El-Mex Bay during the investigation period. Their percentage was 36.7% of the total count and their total numbers were 74,629 individuals with an average of 1866 organisms/m3. The persistent relationships between total copepod counts, copepod orders, and physico-chemical variables suggested that physical factors operate on the copepod communities, either directly to limit maximum distribution along the bay, or indirectly on abundance.

Feeding behaviour of the hydromedusa Aequorea vitrina

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Hans Ulrik RiisgÅrd

2007-06-01

Full Text Available The prey-capture mechanism of the hydromedusa Aequorea vitrina was studied by means of laboratory video-microscope observations. In stagnant water A. vitrina remains stationary with its very long (about 4x bell diameter marginal tentacles motionless hanging down in the water, ready for ambush capture of prey organisms that collide with the tentacles. A. vitrina was found to be efficient at capturing brine shrimps (Artemia salina, less efficient at capturing rotifers (Brachionus plicatilis, and very inefficient at capturing copepods (Acartia tonsa. The initial hauling up of an extended marginal tentacle with an adhering prey is fast (>10 mm s-1. Both the bell margin and the mouth move towards each other so that the captured prey can be transferred from the tentacle to the elongated mouth-lips to be further transported into the mouth and stomach. It takes about 20 s from when an Artemia prey organism encounters a tentacle until it is transferred to the mouth-lips. The subsequent digestion in the stomach takes about 30 min. When A. vitrina encounters a jellyfish-prey (a small medusa of Aurelia aurita, it starts to swim in order to adhere the relatively big prey to its mouth-lips. Then A. vitrina opens its mouth wide to swallow the captured medusa, a process which takes about 15 to 20 min. The subsequent digestion takes 2 to 3 h. Field observations of undisturbed A. vitrina made by snorkelling in the Limfjord (Denmark revealed that the feeding behaviour was similar to that observed in the laboratory in stagnant water. It is concluded that A. vitrina is an ambush-predator, and not a cruising-predatory medusa as previously suggested.

Feast or flee: bioelectrical regulation of feeding and predator evasion behaviors in the planktonic alveolate Favella sp. (Spirotrichia).

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Echevarria, Michael L; Wolfe, Gordon V; Taylor, Alison R

2016-02-01

Alveolate (ciliates and dinoflagellates) grazers are integral components of the marine food web and must therefore be able to sense a range of mechanical and chemical signals produced by prey and predators, integrating them via signal transduction mechanisms to respond with effective prey capture and predator evasion behaviors. However, the sensory biology of alveolate grazers is poorly understood. Using novel techniques that combine electrophysiological measurements and high-speed videomicroscopy, we investigated the sensory biology of Favella sp., a model alveolate grazer, in the context of its trophic ecology. Favella sp. produced frequent rhythmic depolarizations (∼500 ms long) that caused backward swimming and are responsible for endogenous swimming patterns relevant to foraging. Contact of both prey cells and non-prey polystyrene microspheres at the cilia produced immediate mechanostimulated depolarizations (∼500 ms long) that caused backward swimming, and likely underlie aggregative swimming patterns of Favella sp. in response to patches of prey. Contact of particles at the peristomal cavity that were not suitable for ingestion resulted in depolarizations after a lag of ∼600 ms, allowing time for particles to be processed before rejection. Ingestion of preferred prey particles was accompanied by transient hyperpolarizations (∼1 s) that likely regulate this step of the feeding process. Predation attempts by the copepod Acartia tonsa elicited fast (∼20 ms) animal-like action potentials accompanied by rapid contraction of the cell to avoid predation. We have shown that the sensory mechanisms of Favella sp. are finely tuned to the type, location, and intensity of stimuli from prey and predators. © 2016. Published by The Company of Biologists Ltd.

The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China

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Wang Tian

2016-08-01

Full Text Available The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica. Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems.

Antibiotic-induced change of bacterial communities associated with the copepod Nitocra spinipes.

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Anna Edlund

Full Text Available Environmental pressures, such as physical factors, diet and contaminants may affect interactions between microbial symbionts and their multicellular hosts. Despite obvious relevance, effects of antimicrobial contaminants on host-symbiont relations in non-target aquatic organisms are largely unknown. We show that exposure to antibiotics had negative effects on survival and juvenile development of the copepod Nitocra spinipes and caused significant alterations in copepod-associated bacterial communities. The significant positive correlations between indices of copepod development and bacterial diversity indicate that disruption of the microflora was likely to be an important factor behind retarded juvenile development in the experimental animals. Moreover, as evidenced by ribotype distribution in the bacterial clone libraries, the exposure to antibiotics caused a shift in dominance from Betaproteobacteria to Cardinium bacteria; the latter have been shown to cause reproductive manipulations in various terrestrial arthropods. Thus, in addition to providing evidence that the antibiotic-induced perturbation of the microbial community associates with reductions in fitness-related traits of the host, this study is the first record of a copepod serving as a host for endosymbiotic Cardinium. Taken together, our results suggest that (1 antimicrobial substances and possibly other stressors can affect micobiome and symbiont-mediated interactions in copepods and other hosts, and (2 Cardinium endosymbionts may occur in other copepods and affect reproduction of their hosts.

Distribution and diversity of copepods in the Mandovi-Zuari estuarine system, Goa

Digital Repository Service at National Institute of Oceanography (India)

Goswami, S.C.

Truly estuarine and estuarine-marine species were the major components of copepods Neritic and limnetic species were stragglers in this environment and showed fortuitous distribution Monsoonal cycle induced seasonal rhythm on salinity and copepods...

Multimodel inference to quantify the relative importance of abiotic factors in the population dynamics of marine zooplankton

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Everaert, Gert; Deschutter, Yana; De Troch, Marleen; Janssen, Colin R.; De Schamphelaere, Karel

2018-05-01

The effect of multiple stressors on marine ecosystems remains poorly understood and most of the knowledge available is related to phytoplankton. To partly address this knowledge gap, we tested if combining multimodel inference with generalized additive modelling could quantify the relative contribution of environmental variables on the population dynamics of a zooplankton species in the Belgian part of the North Sea. Hence, we have quantified the relative contribution of oceanographic variables (e.g. water temperature, salinity, nutrient concentrations, and chlorophyll a concentrations) and anthropogenic chemicals (i.e. polychlorinated biphenyls) to the density of Acartia clausi. We found that models with water temperature and chlorophyll a concentration explained ca. 73% of the population density of the marine copepod. Multimodel inference in combination with regression-based models are a generic way to disentangle and quantify multiple stressor-induced changes in marine ecosystems. Future-oriented simulations of copepod densities suggested increased copepod densities under predicted environmental changes.

Female-biased sex ratios in marine pelagic copepods: Comment on Gusmao et al. (2013)

DEFF Research Database (Denmark)

Hirst, Andrew G.; Bonnet, D; Conway, DVP

2013-01-01

Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important error...... in their citation of our paper and briefly highlight where future work is needed in order to attribute the causes of strong sex ratio skew seen in some copepod families......Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important errors...

Active prey selection in two pelagic copepods feeding on potentially toxic and non-toxic dinoflagellates

DEFF Research Database (Denmark)

Schultz, Mette; Kiørboe, Thomas

2009-01-01

Grazing on two red tide dinoflagellates, the potentially toxic Karenia mikimotoi and the non-toxic Gyrodinium instriatum, was examined in two species of marine copepods, Pseudocalanus elongatus and Temora longicornis. Both copepods cleared K. mikimotoi at rates that were a little lower but compar......Grazing on two red tide dinoflagellates, the potentially toxic Karenia mikimotoi and the non-toxic Gyrodinium instriatum, was examined in two species of marine copepods, Pseudocalanus elongatus and Temora longicornis. Both copepods cleared K. mikimotoi at rates that were a little lower...

Rapid enzymatic response to compensate UV radiation in copepods.

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María Sol Souza

Full Text Available Ultraviolet radiation (UVR causes physical damage to DNA, carboxylation of proteins and peroxidation of lipids in copepod crustaceans, ubiquitous and abundant secondary producers in most aquatic ecosystems. Copepod adaptations for long duration exposures include changes in behaviour, changes in pigmentation and ultimately changes in morphology. Adaptations to short-term exposures are little studied. Here we show that short-duration exposure to UVR causes the freshwater calanoid copepod, Eudiaptomus gracilis, to rapidly activate production of enzymes that prevent widespread collateral peroxidation (glutathione S-transferase, GST, that regulate apoptosis cell death (Caspase-3, Casp-3, and that facilitate neurotransmissions (cholinesterase-ChE. None of these enzyme systems is alone sufficient, but they act in concert to reduce the stress level of the organism. The interplay among enzymatic responses provides useful information on how organisms respond to environmental stressors acting on short time scales.

Propulsion and perception in intermediate Re regimes: aquatic microcrustacean copepod responses to wake structures.

Science.gov (United States)

Yen, J.; Pender Healy, L. A.; Heaphy, M.

2016-02-01

Flow sensing by the mechanoreceptive cuticular arrays of sensors on copepods has been shaped by over 400 million years of evolution and plays an important role in predator avoidance, foraging, mating, and rheotaxis. These 3D wakes are produced by animal propulsive activities and contain cues that guide these key survival responses. We have demonstrated that the fluid mechanical and chemical information retained in the hydrodynamic envelope can be interpreted by suitable sensor arrays; copepod sensor arrays are capable of perceiving minute differences in wake structures. Temora longicornis, a coastal marine copepod, and Hesperodiaptomus shoshone, a high-alpine freshwater lake copepod, track laminar trails. High-speed videography coupled with high-magnification Schlieren optics enabled us to visualize the deformation of the trail signal and the propulsive movements of the male copepod. Males followed the trail mimic and our observations show clear differences between the marine and freshwater species. Comparative analyses reveal tracking mechanisms that differ in sensor location with respect to the trail and locomotory kinematics. Copepods perform directed motions that lead them to a stimulus source in the absence of other collimating stimuli. Tracking by the copepod around the trail allows it to have one or numerous sensors inside and outside the trail to facilitate edge detection using spatial sampling. The advantage of this remarkable behavior of following trails fast and accurately is to encounter mates or food patches more frequently, thus contributing to population recruitment and energy transfer up the trophic food web. Precise mate and food finding strategies found for pelagic copepods may be a key adaptation, promoting survival in these open-ocean planktonic populations.

Status and recommendations on marine copepod cultivation for use as live feed

DEFF Research Database (Denmark)

Drillet, Guillaume; Frouël, Stéphane; Sichlau, Mie Hylstofte

2011-01-01

Copepods are important crustaceans studied because of their key role in ecology, trophic biology, fisheries management, in modeling the flow of energy and matter, ecotoxicology, aquaculture and aquarium trade. This paper discusses various aspects of the state of knowledge of copepod culture...

High turnover rates of copepod fecal pellets due to Noctiluca scintillans grazing

DEFF Research Database (Denmark)

Kiørboe, Thomas

2003-01-01

Copepod fecal pellet production and vertical flux, as well as vertical distributions of copepods, fecal pellets and the heterotrophic dinoflagellate Noctiluca scintillans were monitored in an upwelling plume off the coast of Brazil during 5 d in austral spring. Less than half (20 to 45%) of the p......Copepod fecal pellet production and vertical flux, as well as vertical distributions of copepods, fecal pellets and the heterotrophic dinoflagellate Noctiluca scintillans were monitored in an upwelling plume off the coast of Brazil during 5 d in austral spring. Less than half (20 to 45...... for fecal pellets at about 0.6 l cell-1 d-1. A simple encounter model suggests that such high clearance rates are feasible. Since N. scintillans occurs at typical abundances of about 106 cells m-2 in temperate seas during spring, summer and autumn, it may contribute significantly to the recycling of rapidly...

Copepod carcasses as microbial hot spots for pelagic denitrification

DEFF Research Database (Denmark)

Glud, Ronnie N.; Grossart, Hans-Peter; Larsen, Morten

2015-01-01

Copepods are exposed to a high non-predatory mortality and their decomposing carcasses act as microniches with intensified microbial activity. Sinking carcasses could thereby represent anoxic microenvironment sustaining anaerobic microbial pathways in otherwise oxic water columns. Using non...... investigated carcass samples and thereby documented the potential for microbial denitrification in carcasses. The nirS gene was occasionally expressed in live copepods, but not as consistently as in carcasses. Incubations of sinking carcasses in 15NO2 3 amended seawater demonstrated denitrification, of which...

Contrasting ecosystem-effects of morphologically similar copepods.

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Blake Matthews

Full Text Available Organisms alter the biotic and abiotic conditions of ecosystems. They can modulate the availability of resources to other species (ecosystem engineering and shape selection pressures on other organisms (niche construction. Very little is known about how the engineering effects of organisms vary among and within species, and, as a result, the ecosystem consequences of species diversification and phenotypic evolution are poorly understood. Here, using a common gardening experiment, we test whether morphologically similar species and populations of Diaptomidae copepods (Leptodiaptomus ashlandi, Hesperodiaptomus franciscanus, Skistodiaptomus oregonensis have similar or different effects on the structure and function of freshwater ecosystems. We found that copepod species had contrasting effects on algal biomass, ammonium concentrations, and sedimentation rates, and that copepod populations had contrasting effects on prokaryote abundance, sedimentation rates, and gross primary productivity. The average size of ecosystem-effect contrasts between species was similar to those between populations, and was comparable to those between fish species and populations measured in previous common gardening experiments. Our results suggest that subtle morphological variation among and within species can cause multifarious and divergent ecosystem-effects. We conclude that using morphological trait variation to assess the functional similarity of organisms may underestimate the importance of species and population diversity for ecosystem functioning.

Prey detection and prey capture in copepod nauplii

DEFF Research Database (Denmark)

Bruno, Eleonora; Borg, Marc Andersen; Kiørboe, Thomas

2012-01-01

Copepod nauplii are either ambush feeders that feed on motile prey or they produce a feeding current that entrains prey cells. It is unclear how ambush and feeding-current feeding nauplii perceive and capture prey. Attack jumps in ambush feeding nauplii should not be feasible at low Reynolds...... (Temora longicornis). We demonstrate that the ambush feeders both detect motile prey remotely. Prey detection elicits an attack jump, but the jump is not directly towards the prey, such as has been described for adult copepods. Rather, the nauplius jumps past the prey and sets up an intermittent feeding...

Structural and functional responses of harpacticoid copepods to anoxia in the Northern Adriatic: an experimental approach

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M. De Troch

2013-06-01

Full Text Available Combined in situ and laboratory studies were conducted to document the effects of anoxia on the structure and functioning of meiobenthic communities, with special focus on harpacticoid copepods. In a first step, anoxia was created artificially by means of an underwater chamber at 24 m depth in the Northern Adriatic, Gulf of Trieste (Mediterranean. Nematodes were found as the most abundant taxon, followed by harpacticoid copepods. While nematode densities were not affected by treatment (anoxia/normoxia or sediment depth, these factors had a significant impact on copepod abundances. Harpacticoid copepod family diversity, in contrast, was not affected by anoxic conditions, only by depth. Ectinosomatidae and Cletodidae were most abundant in both normoxic and anoxic samples. The functional response of harpacticoid copepods to anoxia was studied in a laboratory tracer experiment by adding 13C pre-labelled diatoms to sediment cores in order to test (1 if there is a difference in food uptake by copepods under normoxic and anoxic conditions and (2 whether initial (normoxia feeding of harpacticoid copepods on diatoms results in a better survival of copepods in subsequent anoxic conditions. Independent of the addition of diatoms, there was a higher survival rate in normoxia than anoxia. The supply of additional food did not result in a higher survival rate of copepods in anoxia, which might be explained by the presence of a nutritionally better food source and/or a lack of starvation before adding the diatoms. However, there was a reduced grazing pressure by copepods on diatoms in anoxic conditions. This resulted in a modified fatty acid composition of the sediment. We concluded that anoxia not only impacts the survival of consumers (direct effect but also of primary producers (indirect effect, with important implications for the recovery phase.

[Response of copepod community characteristics to environmental factors in the Backshore Wetland of Expo Garden, Shanghai].

Science.gov (United States)

Chen, Li-Jing; Wu, Yan-Fang; Jing, Yu-Xiang; Wang, Cong; Zhang, Yin-Jiang

2012-11-01

The Backshore Wetland of Expo Garden was the emphasis of the World Expo construction project in Shanghai in 2010, China programming district. We carried out studies on the community structure and spatial-temporal variation of copepod from September 2009 to August 2010. Statistical Product and Service Solutions (SPSS) was used for relevant statistical analysis between physicochemical parameters and copepod standing crop. Canonical correspondence analysis (CCA) was applied to further explore the correlation between copepod species and environmental parameters using CANOCO 4.5. A total of 23 copepod species in 11 genera, 6 families were identified. 5 dominant species of copepod were recorded during the survey period. They were Eucyclops serrulatus, Thermocyclops taihokuensis, Mesocyclops leuckarti, Thermocyclops brevifurcatus and Microcyclops varicans. The annual mean density of copepod was (8.6 +/- 16.6) ind x L(-1) and the biomass was (0.083 6 +/- 0.143 1) mg x L(-1). The standing crop of copepod had its first peak in July, the second in October and the bottom in January. The highest trophic level was measured at Site 1, decreasing along the flowing direction of the water current, and the lowest level was found at Site 10. The Margelf index remained low in winter and spring, but was increased in summer and autumn. The community structure of copepod was analyzed in relation to water quality parameters by canonical correspondence analysis (CCA). Water temperature, pH, nitrate nitrogen, nitrite nitrogen, TN, TP and dissolved oxygen were strongly correlated with the copepod community structure.

Hydrodynamic and Sensory Factors Governing Response of Copepods to Simulated Predation by Balaenid Whales

Directory of Open Access Journals (Sweden)

Alexander J. Werth

2012-01-01

Full Text Available Predator/prey interactions between copepods and balaenid (bowhead and right whales were studied with controlled lab experiments using moving baleen in still water and motionless baleen in flowing water to simulate zooplankton passage toward, into, and through the balaenid oral cavity. Copepods showed a lesser escape response to baleen and to a model head simulating balaenid oral hydrodynamics than to other objects. Copepod escape response increased as water flow and body size increased and was greatest at distances ≥10 cm from baleen and at copepod density = 10,000 m−3. Data from light/dark experiments suggest that escape is based on mechanoreception, not vision. The model head captured 88% of copepods. Results support previous research showing hydrodynamic effects within a whale’s oral cavity create slight suction pressures to draw in prey or at least preclude formation of an anterior compressive bow wave that could scatter or alert prey to the presence of the approaching whale.

Early Miocene amber inclusions from Mexico reveal antiquity of mangrove-associated copepods.

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Huys, Rony; Suárez-Morales, Eduardo; Serrano-Sánchez, María de Lourdes; Centeno-García, Elena; Vega, Francisco J

2016-10-12

Copepods are aquatic microcrustaceans and represent the most abundant metazoans on Earth, outnumbering insects and nematode worms. Their position of numerical world predominance can be attributed to three principal radiation events, i.e. their major habitat shift into the marine plankton, the colonization of freshwater and semiterrestrial environments, and the evolution of parasitism. Their variety of life strategies has generated an incredible morphological plasticity and disparity in body form and shape that are arguably unrivalled among the Crustacea. Although their chitinous exoskeleton is largely resistant to chemical degradation copepods are exceedingly scarce in the geological record with limited body fossil evidence being available for only three of the eight currently recognized orders. The preservation of aquatic arthropods in amber is unusual but offers a unique insight into ancient subtropical and tropical ecosystems. Here we report the first discovery of amber-preserved harpacticoid copepods, represented by ten putative species belonging to five families, based on Early Miocene (22.8 million years ago) samples from Chiapas, southeast Mexico. Their close resemblance to Recent mangrove-associated copepods highlights the antiquity of the specialized harpacticoid fauna living in this habitat. With the taxa reported herein, the Mexican amber holds the greatest diversity of fossil copepods worldwide.

The copepod Calanus spp. (Calanidae) is repelled by polarized light

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Lerner, Amit; Browman, Howard I.

2016-10-01

Both attraction and repulsion from linearly polarized light have been observed in zooplankton. A dichotomous choice experiment, consisting of plankton light traps deployed in natural waters at a depth of 30 m that projected either polarized or unpolarized light of the same intensity, was used to test the hypothesis that the North Atlantic copepod, Calanus spp., is linearly polarotactic. In addition, the transparency of these copepods, as they might be seen by polarization insensitive vs. sensitive visual systems, was measured. Calanus spp. exhibited negative polarotaxis with a preference ratio of 1.9:1. Their transparency decreased from 80% to 20% to 30% in the unpolarized, partially polarized, and electric (e-) vector orientation domains respectively - that is, these copepods would appear opaque and conspicuous to a polarization-sensitive viewer looking at them under conditions rich in polarized light. Since the only difference between the two plankton traps was the polarization cue, we conclude that Calanus spp. are polarization sensitive and exhibit negative polarotaxis at low light intensities (albeit well within the sensitivity range reported for copepods). We hypothesize that Calanus spp. can use polarization vision to reduce their risk of predation by polarization-sensitive predators and suggest that this be tested in future experiments.

Reproductive and life cycle strategies in egg-carrying cyclopoid and free-spawning calanoid copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Sabatini, Marian

1994-01-01

Egg-carrying cyclopoid copepods have lower fecundity and feeding rates, and longer egg hatching times, than free-spawning calanoid copepods. Simple demographic considerations suggest that the lower feeding and fecundity of egg-carrying cyclopoids are adaptations to the potentially elevated...... mortality of ovigerous females, while the shorter egg hatching time and higher feeding and fecundity rates found in free-spawning calanoid copepods represent adaptations to the very high mortality rates experienced by suspended eggs....

Parasites and diseases in marine copepods: Challenges for future mass-production of live feed for fish larva production

DEFF Research Database (Denmark)

Skovgaard, Alf

Copepods are the natural food for many marine fish larvae, and the use of cultured copepods as life feed is, therefore, becoming increasingly important as more marine fish species are being produced in aquaculture. Large-scale cultivation of copepods may be challenged by diseases and parasites....... In nature, marine copepods are hosts for parasitic organisms of many different taxonomic groups, including e.g. dinoflagellates, ciliates, paramyxans, nematodes and even other crustaceans. In addition, several parasites of copepods have yet not been investigated in relation to their taxonomic affiliation...

Feeding on copepod fecal pellets: a new trophic role of dinoflagellates as detritivores

DEFF Research Database (Denmark)

Poulsen, Louise K.; Moldrup, M.; Berge, T.

2011-01-01

Recent field studies indicate that dinoflagellates are key degraders of copepod fecal pellets. This study is the first to publish direct evidence of pellet grazing by dinoflagellates. Feeding and growth on copepod fecal pellets were studied for both heterotrophic (4 species) and mixotrophic...... dinoflagellates (Gyrodinium dominans, Gyrodinium spirale, Diplopsalis lenticula, Protoperidinium depressum) studied fed on fecal pellets. Using natural concentrations of dinoflagellates and copepod fecal pellets, average ingestion rates of 0.2 and 0.1 pellets cell−1 d−1 and clearance rates of between 0.2 and 0...

Impact of the invasive parasitic copepod

NARCIS (Netherlands)

Goedknegt, M.A.; Bedolfe; Drent, J.; van der Meer, J.; Thieltges, D.W.

2018-01-01

Invasive species can indirectly affect native species by modifying parasite–host dynamics and disease occurrence. This scenario applies to European coastal waters where the invasive Pacific oyster (Magallana gigas) co-introduced the parasitic copepod Mytilicola orientalis that spills

Ectoparasitic copepod infestation on a wild population of Neotropical catfish Sciades herzbergii Bloch, 1794: Histological evidences of lesions on host.

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Fogel, Deborah; Fuentes, José Luis; Soto, Luz Marina; Lafuente, Wilson; Moncayo-Estrada, Rodrigo; López, Carlos

2017-12-01

We analyzed the infestation of the attached copepod species Lepeophtheirus sp on a wild population of Sciades herzbergii . The infestation and occurrence of attached copepods were related to body size, maturity and sex of host and the presence of lesions on fish skin were described. In 61 fish specimens (37 males and 24 females), total of 218 ectoparasitic copepods, including 204 mature and 14 immature stages were found. Copepods were attached to different regions of fish body without any regular pattern. The prevalence of infestation was 80.3% and intensity between 1 and 15 copepods/fish. No significant differences were found between sex or maturity and the presence of attached Lepeophtheirus sp. However, a contingency table including both sex and maturity status, and the total number of attached copepod per combined category showed a significant association. A positive correlation was found between body length of fish and intensity of infestation. Similarly, when comparing the infested fish according to group size, we found more copepods on larger individual. Attached copepods were associated with the presence of lesions visible to the naked eye. Histological analyses showed changes in cell architecture when sections of copepod-free tissues and attached copepods were compared.

Climate change affects low trophic level marine consumers: warming decreases copepod size and abundance.

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Garzke, Jessica; Ismar, Stefanie M H; Sommer, Ulrich

2015-03-01

Concern about climate change has re-ignited interest in universal ecological responses to temperature variations: (1) biogeographical shifts, (2) phenology changes, and (3) size shifts. In this study we used copepods as model organisms to study size responses to temperature because of their central role in the pelagic food web and because of the ontogenetic length constancy between molts, which facilitates the definition of size of distinct developmental stages. In order to test the expected temperature-induced shifts towards smaller body size and lower abundances under warming conditions, a mesocosm experiment using plankton from the Baltic Sea at three temperature levels (ambient, ambient +4 °C, ambient -4 °C) was performed in summer 2010. Overall copepod and copepodit abundances, copepod size at all life stages, and adult copepod size in particular, showed significant temperature effects. As expected, zooplankton peak abundance was lower in warm than in ambient treatments. Copepod size-at-immature stage significantly increased in cold treatments, while adult size significantly decreased in warm treatments.

Crustaceans from bitumen clast in Carboniferous glacial diamictite extend fossil record of copepods.

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Selden, Paul A; Huys, Rony; Stephenson, Michael H; Heward, Alan P; Taylor, Paul N

2010-08-10

Copepod crustaceans are extremely abundant but, because of their small size and fragility, they fossilize poorly. Their fossil record consists of one Cretaceous (c. 115 Ma) parasite and a few Miocene (c. 14 Ma) fossils. In this paper, we describe abundant crustacean fragments, including copepods, from a single bitumen clast in a glacial diamictite of late Carboniferous age (c. 303 Ma) from eastern Oman. Geochemistry identifies the source of the bitumen as an oilfield some 100-300 km to the southwest, which is consistent with an ice flow direction from glacial striae. The bitumen likely originated as an oil seep into a subglacial lake. This find extends the fossil record of copepods by some 188 Ma, and of free-living forms by 289 Ma. The copepods include evidence of the extant family Canthocamptidae, believed to have colonized fresh water in Pangaea during Carboniferous times.

Climate alters intraspecific variation in copepod effect traits through pond food webs.

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Charette, Cristina; Derry, Alison M

2016-05-01

Essential fatty acids (EFAs) are primarily generated by phytoplankton in aquatic ecosystems, and can limit the growth, development, and reproduction of higher consumers. Among the most critical of the EFAs are highly unsaturated fatty acids (HUFAs), which are only produced by certain groups of phytoplankton. Changing environmental conditions can alter phytoplankton community and fatty acid composition and affect the HUFA content of higher trophic levels. Almost no research has addressed intraspecific variation in HUFAs in zooplankton, nor intraspecific relationships of HUFAs with body size and fecundity. This is despite that intraspecific variation in HUFAs can exceed interspecific variation and that intraspecific trait variation in body size and fecundity is increasingly recognized to have an important role in food web ecology (effect traits). Our study addressed the relative influences of abiotic selection and food web effects associated with climate change on intraspecific differences and interrelationships between HUFA content, body size, and fecundity of freshwater copepods. We applied structural equation modeling and regression analyses to intraspecific variation in a dominant calanoid copepod, Leptodiatomus minutus, among a series of shallow north-temperate ponds. Climate-driven diurnal temperature fluctuations favored the coexistence of diversity of phytoplankton groups with different temperature optima and nutritive quality. This resulted in unexpected positive relationships between temperature, copepod DHA content and body size. Temperature correlated positively with diatom biovolume, and mediated relationships between copepod HUFA content and body size, and between copepod body size and fecundity. The presence of brook trout further accentuated these positive effects in warm ponds, likely through nutrient cycling and stimulation of phytoplankton resources. Climate change may have previously unrecognized positive effects on freshwater copepod DHA content

Non-consumptive effects of predator presence on copepod reproduction: insights from a mesocosm experiment

DEFF Research Database (Denmark)

Heuschele, Jan; Ceballos, Sara; Borg, Marc Andersen

2014-01-01

Reproduction in planktonic animals depends on numerous biotic and abiotic factors. One of them is predation pressure, which can have both direct consumptive effects on population density and sex ratio, and non-consumptive effects, for example on mating and migration behaviour. In copepods, predator...... vulnerability depends on their sex, motility pattern and mating behaviour. Therefore, copepods can be affected at multiple stages during the mating process. We investigated the reproductive dynamics of the estuarine copepod Eurytemora affinis in the presence and absence of its predator the mysid Neomysis...... treatment, but increased towards the end of the experiment. The proportion of fertilized females was similar in both treatments, but constantly fell behind model predictions using a random mating model. Our results highlight the importance of non-consumptive effects of predators on copepod reproduction...

Ectoparasitic copepod infestation on a wild population of Neotropical catfish Sciades herzbergii Bloch, 1794: Histological evidences of lesions on host

Directory of Open Access Journals (Sweden)

Deborah Fogel

2017-12-01

Full Text Available We analyzed the infestation of the attached copepod species Lepeophtheirus sp on a wild population of Sciades herzbergii. The infestation and occurrence of attached copepods were related to body size, maturity and sex of host and the presence of lesions on fish skin were described. In 61 fish specimens (37 males and 24 females, total of 218 ectoparasitic copepods, including 204 mature and 14 immature stages were found. Copepods were attached to different regions of fish body without any regular pattern. The prevalence of infestation was 80.3% and intensity between 1 and 15 copepods/fish. No significant differences were found between sex or maturity and the presence of attached Lepeophtheirus sp. However, a contingency table including both sex and maturity status, and the total number of attached copepod per combined category showed a significant association. A positive correlation was found between body length of fish and intensity of infestation. Similarly, when comparing the infested fish according to group size, we found more copepods on larger individual. Attached copepods were associated with the presence of lesions visible to the naked eye. Histological analyses showed changes in cell architecture when sections of copepod-free tissues and attached copepods were compared. Keywords: Damages, Fish, Lepeophtheirus, lesions, Sea lice, Parasitism

Myofibril Changes in the Copepod Pseudodiaptomus marinus Exposed to Haline and Thermal Stresses.

Science.gov (United States)

Ibrahim, Ali; Souissi, Anissa; Leray, Aymeric; Héliot, Laurent; Vandenbunder, Bernard; Souissi, Sami

2016-01-01

Copepods are small crustaceans capable to survive in various aquatic environments. Their responses to changes in different external factors such as salinity and temperature can be observed at different integration levels from copepod genes to copepod communities. Until now, no thorough observation of the temperature or salinity effect stresses on copepods has been done by optical microscopy. In this study, we used autofluorescence to visualize these effects on the morphology of the calanoid copepod Pseudodiaptomus marinus maintained during several generations in the laboratory at favorable and stable conditions of salinity (30 psu) and temperature (18°C). Four different stress experiments were conducted: at a sharp decrease in temperature (18 to 4°C), a moderate decrease in salinity (from 30 to 15 psu), a major decrease in salinity (from 30 to 0 psu), and finally a combined stress with a decrease in both temperature and salinity (from 18°C and 30 psu to 4°C and 0 psu). After these stresses, images acquired by confocal laser scanning microscopy (CLSM) revealed changes in copepod cuticle and muscle structure. Low salinity and/or temperature stresses affected both the detection of fluorescence emitted by muscle sarcomeres and the distance between them. In the remaining paper we will use the term sarcomeres to describe the elements located within sarcomeres and emitted autofluorescence signals. Quantitative study showed an increase in the average distance between two consecutive sarcomeres from 2.06 +/- 0.11 μm to 2.44 +/- 0.42 μm and 2.88 +/- 0.45μm after the exposure to major haline stress (18°C, 0 psu) and the combined stress (4°C, 0 psu), respectively. These stresses also caused cuticle cracks which often occurred at the same location, suggesting the cuticle as a sensitive area for osmoregulation. Our results suggest the use of cuticular and muscle autofluorescence as new biomarkers of stress detectable in formalin-preserved P. marinus individuals. Our

Genome-wide identification of nuclear receptor (NR) superfamily genes in the copepod Tigriopus japonicus.

Science.gov (United States)

Hwang, Dae-Sik; Lee, Bo-Young; Kim, Hui-Su; Lee, Min Chul; Kyung, Do-Hyun; Om, Ae-Son; Rhee, Jae-Sung; Lee, Jae-Seong

2014-11-18

Nuclear receptors (NRs) are a large superfamily of proteins defined by a DNA-binding domain (DBD) and a ligand-binding domain (LBD). They function as transcriptional regulators to control expression of genes involved in development, homeostasis, and metabolism. The number of NRs differs from species to species, because of gene duplications and/or lineage-specific gene losses during metazoan evolution. Many NRs in arthropods interact with the ecdysteroid hormone and are involved in ecdysone-mediated signaling in arthropods. The nuclear receptor superfamily complement has been reported in several arthropods, including crustaceans, but not in copepods. We identified the entire NR repertoire of the copepod Tigriopus japonicus, which is an important marine model species for ecotoxicology and environmental genomics. Using whole genome and transcriptome sequences, we identified a total of 31 nuclear receptors in the genome of T. japonicus. Nomenclature of the nuclear receptors was determined based on the sequence similarities of the DNA-binding domain (DBD) and ligand-binding domain (LBD). The 7 subfamilies of NRs separate into five major clades (subfamilies NR1, NR2, NR3, NR4, and NR5/6). Although the repertoire of NR members in, T. japonicus was similar to that reported for other arthropods, there was an expansion of the NR1 subfamily in Tigriopus japonicus. The twelve unique nuclear receptors identified in T. japonicus are members of NR1L. This expansion may be a unique lineage-specific feature of crustaceans. Interestingly, E78 and HR83, which are present in other arthropods, were absent from the genomes of T. japonicus and two congeneric copepod species (T. japonicus and Tigriopus californicus), suggesting copepod lineage-specific gene loss. We identified all NR receptors present in the copepod, T. japonicus. Knowledge of the copepod nuclear receptor repertoire will contribute to a better understanding of copepod- and crustacean-specific NR evolution.

Predation vulnerability of planktonic copepods: consequences of predator foraging strategies and prey sensory abilities

DEFF Research Database (Denmark)

Viitasalo, M; Kiørboe, T; Flinkman, J.

1998-01-01

We investigated the vulnerability of 2 copepod species (Eurytemora affinis and Temora longicornis) to predation by predators with different foraging modes, three-spined stickleback Gasterosteus aculeatus juveniles and mysid shrimps Neomysis integer. Copepods were videofilmed escaping from predators...

Prymnesium parvum exotoxins affect the grazing and viability of the calanoid copepod Eurytemora affinis

DEFF Research Database (Denmark)

Sopanen, S.; Koski, Marja; Uronen, P.

2008-01-01

The calanoid copepod Eurytemora affinis from the northern Baltic Sea was exposed to cell-free filtrates of the toxic haptophyte Prymnesium parvum as well as to cell mixtures of P. parvum and Rhodomonas salina. To test the effects of P. parvum exudates and allelopathy on selective grazers, copepods...... cultures were grown in nutrient-balanced (+NP) or limited (-N or -P) media to obtain different levels of toxicity. Survival, ingestion, faecal pellet production rates and egg production were measured over 3 d, together with measurements of P. parvum toxicity (hemolytic activity) (HA). Most of the copepods...... on grazers, and these effects are stronger under nutrient-depleted conditions; however, the presence of good-quality food lowers harmful effects for copepods. The negative effects caused either by direct intoxication or by food limitation following from strong allelopathic effects of P. parvum on other...

EFFECT OF MICROALGAE ON GROWTH AND FATTY ACID PROFILES OF HARPACTICOID COPEPOD, Tisbe holothuriae

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Gede Suwarthama Sumiarsa

2009-12-01

Full Text Available Growth of marine copepods is influenced by feed. The purposes of this trial were to observe both growth and fatty acid compositions of harpacticoid copepod nauplii, Tisbe holothuriae by feeding with several microalgal species in laboratory: (A Isochrysis tahiti; (B Nannochloropsis oculata; (C Rhodomonas sp., and (D Tetraselmis chuii. The trial was carried out for 35 days with randomized complete design and triplicates in each treatment. The results showed that final copepod nauplii densities were not significantly different (P>0.05 in all treatments. However, lipid content of copepod nauplii fed with T. chuii was significantly higher (P<0.05 compared to that of other treatments while fatty acid profiles of EPA, DHA and DHA/EPA ratios showed both insignificant and significant differences among treatments.

Swimming Behavior and Flow Geometry: A Fluid Mechanical Study of the Feeding Currents in Calanoid Copepods

Science.gov (United States)

Jiang, Houshuo; Meneveau, Charles; Osborn, Thomas R.

2003-11-01

Copepods are small crustaceans living in oceans and fresh waters and play an important role in the marine and freshwater food webs. As they are the biggest biomass in the oceans some call them "the insects of the sea". Previous laboratory observations have shown that the fluid mechanical phenomena occurring at copepod body scale are crucial for the survival of copepods. One of the interesting phenomena is that many calanoid copepods display various behaviors to create the feeding currents for the purpose of capturing food particles. We have developed a fluid mechanical model to study the feeding currents. The model is a self-propelled body model in that the Navier-Stokes equations are properly coupled with the dynamic equations for the copepod's body. The model has been solved both analytically using the Stokes approximation with a spherical body shape and numerically using CFD with a realistic body shape.

The fate of lipids during development and cold-storage of eggs in the laboratory-reared calanoid copepod, Acartia tonsa Dana, and in response to different algal diets

DEFF Research Database (Denmark)

Støttrup, Josianne; Bell, J.G.; Sargent, J.R.

1999-01-01

: the cryptophyte Rhodomonas baltica, the haptophyte Isochrysis galbana clone T- iso, the diatom Thalassiosira weissflogii and the dinoflagellate Heterocapsa triquetra. Further, the effect of cold storage of eggs on the lipid composition of the newly hatched nauplii was examined. During development, the fatty acid...... composition changes from a tendency towards high levels of long-chain polyunsaturated fatty acids in the early developmental stages towards a tendency to accumulate more saturated and monounsaturated fatty acids in the later developmental stages. However, the content and composition of polyunsaturated fatty...

Sex, sex-ratios, and the dynamics of pelagic copepod populations

DEFF Research Database (Denmark)

Kiørboe, Thomas

2006-01-01

equal adult sex ratios in field populations. Winter population densities are orders of magnitude less than the critical population density required for population persistence, but populations survive winter seasons as resting eggs in the sediment. Population growth in these species is potentially high...... because they have on average a factor of 2 higher egg production rates than other pelagic copepods. Secondly, other copepods require only one mating to stay fertile, and populations of these species have strongly female-skewed adult sex-ratios in field populations. Resting eggs have not been described...

Checklist of copepods (Crustacea: Calanoida, Cyclopoida,Harpacticoida) from Wyoming, USA, with new state records

Science.gov (United States)

Presentation of a comprehensive checklist of the copepod fauna of Wyoming, USA with 41 species of copepods; based on museum specimens, literature reviews, and active surveillance. Of these species 19 were previously unknown from the state. This checklist includes species in the families Centropagida...

Dimethyl sulfide triggers search behavior in copepods

NARCIS (Netherlands)

Steinke, M.; Stefels, J.; Stamhuis, E.J.

The oceans are nutritionally dilute, and finding food is a major challenge for many zooplanktonic predators. Chemodetection is necessary for successful prey-capture, but little is known about the infochemicals involved in the interaction between herbivorous copepods and their phytoplankton prey. We

Host-specific and pH-dependent microbiomes of copepods in an extensive rearing system

DEFF Research Database (Denmark)

Skovgaard, Alf; Castro Mejia, Josue Leonardo; Hansen, Lars Hestbjerg

2015-01-01

copepod production system. Light microscopy and scanning electron microscopy revealed that bacteria were primarily found attached to the exoskeleton of copepods although a few bacteria were also found in the gut as well as internally in skeletal muscle tissue. Through 16S rRNA gene-targeted denaturing...

Life cycle strategies of copepods in coastal upwelling zones

Science.gov (United States)

Peterson, W.

1998-06-01

Life cycles of copepods of coastal upwelling zones are of the multigenerational type—as many as 10 or more generations may be produced each year, depending upon water temperature, food concentration and length of the upwelling season. Abundant food resources and moderate temperature convey advantages to those copepods living in coastal upwelling zones, however, there is a clear disadvantage in that coastal upwelling zones are highly advective environments. Typically, water circulation patterns are such that surface waters are carried offshore, deeper waters carried onshore and most of the water column over the continental shelf is moving equatorward. The challenge to copepod species that inhabit upwelling systems is life cycle closure—how do eggs, nauplii, juveniles and adults avoid being swept out of these ecosystems in the face of persistent transport out of the system? In this review, I first list the species which dominate coastal upwelling ecosystems then discuss three variations on the multigenerational life cycle scheme that are observed in upwelling systems. The latter part of the review is devoted to discussion of how individuals are retained in the productive continental shelf waters within coastal upwelling ecosystems. The suggestion is made that the only copepod species that successfully achieve life cycle closure in such systems are those that are preadapted to upwelling circulation patterns. Our quantitative understanding of the relative importance of physical factors (such as advection) and biological factors (birth, growth, and mortality) on life cycle strategies and population dynamics is quite rudimentary. It would help our understanding if there were more field studies and more computer modeling studies that focused on seasonal cycles of abundance, development times and vertical distribution of life cycle stages, and measurements of water circulation patterns.

COPEPOD: The Coastal & Oceanic Plankton Ecology, Production, & Observation Database

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal & Oceanic Plankton Ecology, Production, & Observation Database (COPEPOD) provides NMFS scientists with quality-controlled, globally distributed...

Pontellid copepods, Labidocera spp., affected by ocean acidification: A field study at natural CO2 seeps.

Science.gov (United States)

Smith, Joy N; Richter, Claudio; Fabricius, Katharina E; Cornils, Astrid

2017-01-01

CO2 seeps in coral reefs were used as natural laboratories to study the impacts of ocean acidification on the pontellid copepod, Labidocera spp. Pontellid abundances were reduced by ∼70% under high-CO2 conditions. Biological parameters and substratum preferences of the copepods were explored to determine the underlying causes of such reduced abundances. Stage- and sex-specific copepod lengths, feeding ability, and egg development were unaffected by ocean acidification, thus changes in these physiological parameters were not the driving factor for reduced abundances under high-CO2 exposure. Labidocera spp. are demersal copepods, hence they live amongst reef substrata during the day and emerge into the water column at night. Deployments of emergence traps showed that their preferred reef substrata at control sites were coral rubble, macro algae, and turf algae. However, under high-CO2 conditions they no longer had an association with any specific substrata. Results from this study indicate that even though the biology of a copepod might be unaffected by high-CO2, Labidocera spp. are highly vulnerable to ocean acidification.

Pontellid copepods, Labidocera spp., affected by ocean acidification: A field study at natural CO2 seeps.

Directory of Open Access Journals (Sweden)

Joy N Smith

Full Text Available CO2 seeps in coral reefs were used as natural laboratories to study the impacts of ocean acidification on the pontellid copepod, Labidocera spp. Pontellid abundances were reduced by ∼70% under high-CO2 conditions. Biological parameters and substratum preferences of the copepods were explored to determine the underlying causes of such reduced abundances. Stage- and sex-specific copepod lengths, feeding ability, and egg development were unaffected by ocean acidification, thus changes in these physiological parameters were not the driving factor for reduced abundances under high-CO2 exposure. Labidocera spp. are demersal copepods, hence they live amongst reef substrata during the day and emerge into the water column at night. Deployments of emergence traps showed that their preferred reef substrata at control sites were coral rubble, macro algae, and turf algae. However, under high-CO2 conditions they no longer had an association with any specific substrata. Results from this study indicate that even though the biology of a copepod might be unaffected by high-CO2, Labidocera spp. are highly vulnerable to ocean acidification.

Calanoid copepods of the International Indian Ocean Expedition

Digital Repository Service at National Institute of Oceanography (India)

Stephen, R.; Devi, K.S.; Meenakshikunjamma, P.P.; Gopalakrishnan, T.C.; Saraswathy, M.

The distribution of calanoid copepods is discussed based on the subsorted taxa of the International Indian Ocean Expedition samples. Of the 32 calanoid taxa only 17 groups were considered as significant components. The family Eycalanidae...

Biochemical composition of the promising live feed tropical calanoid copepod Pseudodiaptomus annadalei (Sewell 1991) cultured in Taiwaneese outdoor ponds

DEFF Research Database (Denmark)

Rayner, Thomas Allan; Jørgensen, Niels. O.G.; Blanda, Elisa

2015-01-01

The use of copepods as live feed has shown good potential, and in Taiwan copepods are harvested specifically as live feed for fin-fish production. The calanoid copepod Pseudodiaptomus annandalei is a species found typically in Taiwanese aquaculture and in the rest of the Indo-Pacific region...

Perceiving the algae: How feeding-current feeding copepods detect their nonmotile prey

DEFF Research Database (Denmark)

Goncalves, Rodrigo J.; Kiørboe, Thomas

2015-01-01

demonstrate that (1) long-range chemical detection is incompatible with known algal leakage rates and reasonable assumptions of sensitivity, (2) that near-field chemical detection is constrained by diffusion across the boundary layer of the sensor and takes longer than observed near-contact times, and (3......Feeding-current feeding copepods detect and capture prey individually, but the mechanism by which nonmotile prey is detected has been unclear. Early reports that copepods detect phytoplankton prey at distances of one body length or more led to the hypothesis that solutes leaking from the prey would......) that most reported detection distances are well predicted by models of fluid mechanical signal generation and detection. We conclude that near-field mechanoreception is the common prey detection mode in pelagic copepods. Prey detection distances are thus governed mainly by the reach of the feeding...

Tumour-like anomaly of copepods-an evaluation of the possible causes in Indian marine waters

Digital Repository Service at National Institute of Oceanography (India)

Jagadeesan, L.; Jyothibabu, R.

so far to prove conclusively the mechanism involved in developing TLA in copepods. TLA in copepods are considered as a potential threat to the well-being of the aquatic food web, which prompted us to assess these abnormalities in Indian marine waters...

Observations of copepod feeding and vertical distribution under natural turbulent conditions in the North Sea

DEFF Research Database (Denmark)

Visser, Andre; Saito, H.; Saiz, E.

2001-01-01

We present results of simultaneous measurements of turbulent- dissipation rate, zooplankton vertical distribution and copepod gut pigments in the northern North Sea. Analysis shows that some, but not all, copepods (by species, sex and stage) exhibit significant dependence on turbulence in respect...

Calanoid Copepod Behavior in Thin Layer Shear Flows: Freshwater Versus Marine

Science.gov (United States)

Skipper, A. N.; Webster, D. R.; Yen, J.

2015-11-01

Marine copepods have been shown to behaviorally respond to vertical gradients of horizontal velocity and aggregate around thin layers. The current study addresses whether a freshwater copepod from an alpine lake demonstrates similar behavior response. Hesperodiaptomus shoshone is often the greatest biomass in alpine lakes and is the dominant zooplankton predator within its environment. The hypothesis is that H. shoshone responds to vertical gradients of horizontal velocity, which are associated with river outflows from alpine lakes, with fine-scale changes in swimming kinematics. The two calanoid copepods studied here, H. shoshone (freshwater) and Calanus finmarchicus(marine), are of similar size (2 - 4 mm), have similar morphologies, and utilize cruising as their primary swimming mode. The two animals differ not only in environment, but also in diet; H. shoshone is a carnivore, whereas C. finmarchicusis an herbivore. A laminar, planar jet (Bickley) was used in the laboratory to simulate a free shear flow. Particle image velocimetry (PIV) quantified the flow field. The marine species changed its swimming behavior significantly (increased swimming speed and turning frequency) and spent more time in the layer (40% vs. 70%) from control to treatment. In contrast, the freshwater species exhibited very few changes in either swimming behavior or residence time. Swimming kinematics and residence time results were also similar between males and females. Unlike the marine copepod, the results suggest the environmental flow structure is unimportant to the freshwater species.

Copepod Behavior Response in an Internal Wave Apparatus

Science.gov (United States)

Webster, D. R.; Jung, S.; Haas, K. A.

2017-11-01

This study is motivated to understand the bio-physical forcing in zooplankton transport in and near internal waves, where high levels of zooplankton densities have been observed in situ. A laboratory-scale internal wave apparatus was designed to create a standing internal wave for various physical arrangements that mimic conditions observed in the field. A theoretical analysis of a standing internal wave inside a two-layer stratification system including non-linear wave effects was conducted to derive the expressions for the independent variables controlling the wave motion. Focusing on a case with a density jump of 1.0 σt, a standing internal wave was generated with a clean interface and minimal mixing across the pycnocline. Spatial and frequency domain measurements of the internal wave were evaluated in the context of the theoretical analysis. Behavioral assays with a mixed population of three marine copepods were conducted in control (stagnant homogeneous fluid), stagnant density jump interface, and internal wave flow configurations. In the internal wave treatment, the copepods showed an acrobatic, orbital-like motion in and around the internal wave region (bounded by the crests and the troughs of the waves). Trajectories of passive, neutrally-buoyant particles in the internal wave flow reveal that they generally oscillate back-and-forth along fixed paths. Thus, we conclude that the looping, orbital trajectories of copepods in the region near the internal wave interface are due to animal behavior rather than passive transport.

Influence of N, P additions on the transfer of nickel from phytoplankton to copepods

International Nuclear Information System (INIS)

Wang Minghua; Wang Dazhi; Wang Guizhong; Huang Xuguang; Hong Huasheng

2007-01-01

We examined the influence of macronutrient (nitrate and phosphate) additions on Ni uptake by phytoplankton (Prorocentrum donghaiense and Skeletonema costatum) and its subsequent transfer to marine copepods (Calanus sinicus and Labidocera euchaeta). Ni uptake by phytoplankton after 24 h of exposure was markedly dependent on nutrient conditions, with a higher nutrient quota facilitating Ni accumulation in the algae. Trophic transfer was quantified by measurements of the Ni assimilation efficiency in C. sinicus and L. euchaeta, feeding on the algae under different nutrient treatments. Ni assimilation efficiency generally increased with an increase of nutrient concentration in the algae. A significant positive-correlation was found between the Ni assimilation efficiencies of the copepods and the %intracellular Ni in the algal cells. However, ambient nutritional conditions had little effect on the physiological turnover rate constant of Ni by copepods. Thus, nutrient enrichment may lead to an increase in Ni uptake and transfer in marine plankton. - Higher nitrate or phosphate levels will facilitate the biological uptake of Ni by phytoplankton and subsequently improve its transfer to marine copepods

Mandibular gnathobases of marine planktonic copepods – feeding tools with complex micro- and nanoscale composite architectures

Directory of Open Access Journals (Sweden)

Jan Michels

2015-03-01

Full Text Available Copepods are dominant members of the marine zooplankton. Their diets often comprise large proportions of diatom taxa whose silicified frustules are mechanically stable and offer protection against grazers. Despite of this protection, many copepod species are able to efficiently break even the most stable frustule types. This ability requires specific feeding tools with mechanically adapted architectures, compositions and properties. When ingesting food, the copepods use the gnathobases of their mandibles to grab and, if necessary, crush and mince the food items. The morphology of these gnathobases is related to the diets of the copepods. Gnathobases of copepod species that mainly feed on phytoplankton feature compact and stable tooth-like structures, so-called teeth. In several copepod species these gnathobase teeth have been found to contain silica. Recent studies revealed that the siliceous teeth are complex microscale composites with silica-containing cap-like structures located on chitinous exoskeleton sockets that are connected with rubber-like bearings formed by structures with high proportions of the soft and elastic protein resilin. In addition, the silica-containing cap-like structures exhibit a nanoscale composite architecture. They contain some amorphous silica and large proportions of the crystalline silica type α-cristobalite and are pervaded by a fine chitinous fibre network that very likely serves as a scaffold during the silicification process. All these intricate composite structures are assumed to be the result of a coevolution between the copepod gnathobases and diatom frustules in an evolutionary arms race. The composites very likely increase both the performance of the siliceous teeth and their resistance to mechanical damage, and it is conceivable that their development has favoured the copepods’ dominance of the marine zooplankton observed today.

Copepod swarm in the Campbell Bay (Andaman Sea)

Digital Repository Service at National Institute of Oceanography (India)

Goswami, S.C.; Rao, T.S.S.

)forming 91.9 to 96.1 c of the total copepod population and constituted mainly by 4 species of Pontellopsis was recorded The species in order of abundance were Pontella spinipes Giesbrecht Pontellopsis regalis (Dana), Pontella princeps Dana and P...

A trait database for marine copepods

Science.gov (United States)

Brun, Philipp; Payne, Mark R.; Kiørboe, Thomas

2017-02-01

The trait-based approach is gaining increasing popularity in marine plankton ecology but the field urgently needs more and easier accessible trait data to advance. We compiled trait information on marine pelagic copepods, a major group of zooplankton, from the published literature and from experts and organized the data into a structured database. We collected 9306 records for 14 functional traits. Particular attention was given to body size, feeding mode, egg size, spawning strategy, respiration rate, and myelination (presence of nerve sheathing). Most records were reported at the species level, but some phylogenetically conserved traits, such as myelination, were reported at higher taxonomic levels, allowing the entire diversity of around 10 800 recognized marine copepod species to be covered with a few records. Aside from myelination, data coverage was highest for spawning strategy and body size, while information was more limited for quantitative traits related to reproduction and physiology. The database may be used to investigate relationships between traits, to produce trait biogeographies, or to inform and validate trait-based marine ecosystem models. The data can be downloaded from PANGAEA, PANGAEA.862968" target="_blank">doi:10.1594/PANGAEA.862968.

Comparison of copepod collection efficiencies by three commonly used plankton nets: A case study in Bohai Sea, China

Science.gov (United States)

Chen, Hongju; Yu, Hao; Liu, Guangxing

2016-12-01

Selection of net with a suitable mesh size is a key concern in the quantitative assessment of zooplankton, which is crucial to understand pelagic ecosystem processes. This study compared the copepod collecting efficiency of three commonly used plankton nets, namely, the China standard coarse net (505 μm mesh), the China standard fine net (77 μm), and the WP-2 net (200 μm). The experiment was performed at six stations in the Bohai Sea during the autumn of 2012. The coarse net substantially under-sampled small individuals (body widths copepod species but failed to collect rare species. The WP-2 net appeared to be a compromise of the two other nets, collecting both small copepods and rare species. The abundance of copepods collected by the coarse net (126.4 ± 86.5 ind m-3) was one to two orders of magnitude lower than that by the WP-2 net (5802.4 ± 2595.4 ind m-3), and the value of the fine net (11117.0 ± 4563.41 ind m-3) was nearly twice that of the WP-2 net. The abundance of large copepods ( i.e., adult Calanus sinicus) in the three nets showed no significant differences, but the abundance of small copepods declined with decreasing mesh size. The difference in abundance resulted from the under-sampling of small copepods with body widths < 672 μm and < 266 μm by the coarse and WP-2 nets, respectively.

Micrallecto uncinata n. gen., n.sp., a parasitic copepod from a remarkable host, the pteropod Pneumoderma

NARCIS (Netherlands)

Stock, Jan H.

1971-01-01

A new genus and species of copepod crustacean parasite, Micrallecto uncinata, is described from Pneumoderma pygmaeum (Tesch, 1903), a gymnosome pteropod (Mollusca) collected West of Bermuda. The parasite probably belongs to the family Splanchnotrophidae and is the first copepod associate reported

The effects of bis(tributyltin) oxide on the development, reproduction and sex ratio of calanoid copepod Pseudodiaptomus marinus

Science.gov (United States)

Huang, Ying; Zhu, Liyan; Liu, Guangxing

2006-08-01

In order to study the biological effects by bis(tributyltin) oxide (TBTO) exposure, chronic toxicity tests were conducted on the calanoid copepod Pseudodiaptomus marinus over two generations. The results indicated that nauplii were more sensitive than copepodites. F1 copepods were more vulnerable than F0 copepods and a drastic increase in mortality was observed as the TBTO concentration became higher. Exposure of copepods to 60 ng l -1 TBTO concentration reduced the fecundity and resulted in some females being infecund (in the F0 generation). The time to the first egg sac for females in the F1 generation exposed to 6 ng l -1 TBTO concentration was significantly reduced, and the fecundity of this generation was increased. The female-to-male ratio in the F1 generation exposed to 20 ng l -1 TBTO concentration was significantly reduced. These results show that the current ambient TBT concentration may influence populations of copepods in the coastal environment.

Unsteady motion: escape jumps in planktonic copepods, their kinematics and energetics

Science.gov (United States)

Kiørboe, Thomas; Andersen, Anders; Langlois, Vincent J.; Jakobsen, Hans H.

2010-01-01

We describe the kinematics of escape jumps in three species of 0.3–3.0 mm-sized planktonic copepods. We find similar kinematics between species with periodically alternating power strokes and passive coasting and a resulting highly fluctuating escape velocity. By direct numerical simulations, we estimate the force and power output needed to accelerate and overcome drag. Both are very high compared with those of other organisms, as are the escape velocities in comparison to startle velocities of other aquatic animals. Thus, the maximum weight-specific force, which for muscle motors of other animals has been found to be near constant at 57 N (kg muscle)−1, is more than an order of magnitude higher for the escaping copepods. We argue that this is feasible because most copepods have different systems for steady propulsion (feeding appendages) and intensive escapes (swimming legs), with the muscular arrangement of the latter probably adapted for high force production during short-lasting bursts. The resulting escape velocities scale with body length to power 0.65, different from the size-scaling of both similar sized and larger animals moving at constant velocity, but similar to that found for startle velocities in other aquatic organisms. The relative duration of the pauses between power strokes was observed to increase with organism size. We demonstrate that this is an inherent property of swimming by alternating power strokes and pauses. We finally show that the Strouhal number is in the range of peak propulsion efficiency, again suggesting that copepods are optimally designed for rapid escape jumps. PMID:20462876

PRELIMINARY STUDY ON POPULATION DYNAMIC OF HARPACTICOID COPEPOD Euterpina acutifrons IN CULTURE CONDITION

Directory of Open Access Journals (Sweden)

Philip Teguh Imanto

2007-12-01

Full Text Available The most important factor to high mortality rate in larval rearing is feeding success in early larval stage related to kind and size of natural live food. Copepod basically is the main source of natural food in the open ocean having some advantages such as smaller size of nauplii, attractive movement and high nutritional value. Observation on population dynamic of harpacticoid copepod Euterpina acutifrons was carried out using 5-L plastic bucket with initial density 100 ind./L. Green algae Nannochloropsis sp. was added to culture media at density of 50,000 cells/mL as a basic feed and additional feeds given were wheat flour (group A and chicken liver (group B at a rate of 50 mg/bucket. The result showed that there was no difference on population pattern in both groups where the incubation time took eight days to hatch, from nauplii to the copepodite stage was three days and from copepodite to adult copepod took five-to-six days. The differences came up from population number: in group (A the highest number of copepod-bearing-egg was only 133 ind., nauplii production up to 62,833 ind. and number of copepodites was 22,333 ind. lower compared to group (B with the highest copepod-egg was 308 ind., nauplii was 113,333 ind. and copepodite was 51,167 ind. The conclusion pointed out that the kind of food did not influence population pattern (quality but gave effect to population growth.

Distribution of pelagic harpacticoid copepods from the Indian ocean

Digital Repository Service at National Institute of Oceanography (India)

Haridas, P.; Rao, T.S.S.

Pelagic harpacticoid copepods have been studied from the International Indian Ocean Expedition collections. Macrosetella gracilis and Miracia efferata were the most common species of harpacticoids with high densities near land masses. Other three...

Consequences of acclimation to Microcystis on the selective feeding behavior of the calanoid copepod Eudiaptomus gracilis

NARCIS (Netherlands)

Ger, K.A.; Panosso, R.; Lürling, M.

2011-01-01

We tested the hypothesis that calanoid copepods would adapt to extended periods of Microcystis exposure by increasing selective feeding on alternative food. Copepod (Eudiaptomus gracilis) clearance rates were compared before and after a 5-d acclimation to Microcystis aeruginosa using paired food

Resting eggs in free living marine and estuarine copepods

DEFF Research Database (Denmark)

Holm, Mark Wejlemann; Kiørboe, Thomas; Brun, Philipp Georg

2018-01-01

Marine free living copepods can survive harsh periods and cope with seasonal fluctuations in environmental conditions using resting eggs (embryonic dormancy). Laboratory experiments show that temperature is the common driver for resting egg production. Hence, we hypothesize (i) that seasonal...... temperature variation, rather than variation in food abundance is the main driver for the occurrence of the resting eggs strategy in marine and estuarine copepod species; and (ii) that the thermal boundaries of the distribution determine where resting eggs are produced and whether they are produced to cope...... with warm or cold periods. We compile literature information on the occurrence of resting egg production and relate this to spatio-temporal patterns in sea surface temperature and chlorophyll a concentration obtained from satellite observations. We find that the production of resting eggs has been reported...

Response of copepods to elevated pCO2 and environmental copper as co-stressors--a multigenerational study.

Directory of Open Access Journals (Sweden)

Susan C Fitzer

Full Text Available We examined the impacts of ocean acidification and copper as co-stressors on the reproduction and population level responses of the benthic copepod Tisbe battagliai across two generations. Naupliar production, growth, and cuticle elemental composition were determined for four pH values: 8.06 (control; 7.95; 7.82; 7.67, with copper addition to concentrations equivalent to those in benthic pore waters. An additive synergistic effect was observed; the decline in naupliar production was greater with added copper at decreasing pH than for decreasing pH alone. Naupliar production modelled for the two generations revealed a negative synergistic impact between ocean acidification and environmentally relevant copper concentrations. Conversely, copper addition enhanced copepod growth, with larger copepods produced at each pH compared to the impact of pH alone. Copepod digests revealed significantly reduced cuticle concentrations of sulphur, phosphorus and calcium under decreasing pH; further, copper uptake increased to toxic levels that lead to reduced naupliar production. These data suggest that ocean acidification will enhance copper bioavailability, resulting in larger, but less fecund individuals that may have an overall detrimental outcome for copepod populations.

Effect of grazing-mediated dimethyl sulfide (DMS) production on the swimming behavior of the copepod Calanus helgolandicus.

Science.gov (United States)

Breckels, Mark N; Bode, Nikolai W F; Codling, Edward A; Steinke, Michael

2013-07-15

Chemical interactions play a fundamental role in the ecology of marine foodwebs. Dimethyl sulfide (DMS) is a ubiquitous marine trace gas that acts as a bioactive compound by eliciting foraging behavior in a range of marine taxa including the copepod Temora longicornis. Production of DMS can rapidly increase following microzooplankton grazing on phytoplankton. Here, we investigated whether grazing-induced DMS elicits an increase in foraging behavior in the copepod Calanus helgolandicus. We developed a semi-automated method to quantify the effect of grazing-mediated DMS on the proportion of the time budget tethered females allocate towards slow swimming, typically associated with feeding. The pooled data showed no differences in the proportion of the 25 min time budget allocated towards slow swimming between high (23.6 ± 9.74%) and low (29.1 ± 18.33%) DMS treatments. However, there was a high degree of variability between behavioral responses of individual copepods. We discuss the need for more detailed species-specific studies of individual level responses of copepods to chemical signals at different spatial scales to improve our understanding of chemical interactions between copepods and their prey.

Laboratory scale photobioreactor for high production of microalgae Rhodomonas salina used as food for intensive copepod cultures

DEFF Research Database (Denmark)

Thuy, Minh Vu Thi; Jepsen, Per Meyer; Hansen, Benni Winding

Introduction Microalgae are essential feeds for many cultured molluscs, larvae of marine fishes, crustaceans as well as other important live feeds including rotifers, Artemia and copepods (Muller-Feuga, 2000). Microalgae are grown either in open culture systems (ponds) or closed systems (photobio......Introduction Microalgae are essential feeds for many cultured molluscs, larvae of marine fishes, crustaceans as well as other important live feeds including rotifers, Artemia and copepods (Muller-Feuga, 2000). Microalgae are grown either in open culture systems (ponds) or closed systems...... for copepods (Støttrup and Jensen, 1990; Zhang et al., 2013). Despite the benefit of using R. salina in cultivation of copepods, to our knowledge, there is no report on the production of this microalga at industrial scale to supply sufficient food for mass production of copepods. We intend to conduct the basic...... was cultivated continuously at temperature of 20ºC and salinity of 30ppt in two tubular PBRs with addition of CO2. The experiment was run two times and each PBR in 18 - 30 days. Periodically, the algae were sampled for analyzing the growth, biochemical composition and production. An exponential light model...

Copepod composition, abundance and diversity in Makupa Creek ...

African Journals Online (AJOL)

Evenness (J) was, however, relatively constant (0.67 to 0.84) during the entire sampling period. These results point to suppressed copepod diversity and abundance in Makupa Creek, and possible reasons for this, which may include environmental degradation caused by pollution, are presented. Western Indian Ocean ...

Survival, growth performance and immune capacity of the juvenile lined seahorse Hippocampus erectus fed with rifampicin-treated copepods.

Science.gov (United States)

Lin, Tingting; Wang, Changbo; Liu, Xin; Gao, Fen; Xiao, Dongxue; Zhang, Dong; Zhu, Xialian

2017-06-19

Gastrointestinal disease is one of the most serious diseases in cultured seahorse juveniles. Treatment with antimicrobials of live food (i.e. copepods and Artemia) that is used to feed the juveniles may be a promising measure to alleviate the occurrence of gastrointestinal disease. However, relevant investigations are rare. In the present study, we first investigated the antimicrobial efficacies on bacteria within copepods that were treated with 4 antimicrobials, including 3 antibiotics (i.e. enrofloxacin hydrochloride, oxytetracycline and rifampicin [RFP]) that are approved for use in aquaculture and 1 disinfectant (i.e. povidone iodine). We then assessed the effects of copepods treated with the antimicrobial that had the best antimicrobial efficacy on survival, growth performance and immune capacity of juvenile lined seahorses Hippocampus erectus. The results showed that RFP had the best antimicrobial efficacy on both Pseudoalteromonas spp. and Vibrio spp., 2 dominant bacteria with potential pathogenicity within the copepods; the proper concentration of RFP was 6 mg l-1. Moreover, H. erectus juveniles fed with RFP-treated copepods demonstrated an improved survivorship and immune capacity and had a lower abundance of pathogenic bacteria within their gastrointestinal tracts compared to juveniles fed with untreated copepods. These results suggest that treating live food with RFP is a potential measure for reducing the incidence of gastrointestinal disease in seahorse juveniles.

Histopathology of a mesoparasitic hatschekiid copepod in hospite: does Mihbaicola sakamakii (Copepoda: Siphonostomatoida: Hatschekiidae) fast within the host fish tissue?

Science.gov (United States)

Hirose, Euichi; Uyeno, Daisuke

2014-08-01

Mihbaicola sakamakii is a mesoparasitic copepod that infests the branchiostegal membranes of groupers (Perciformes: Serranidae). In this study, we observed M. sakamakii within host tissue. Histologically, copepods were found enclosed inside a pouch composed of the thickened epidermis of the host, tightly encased on all sides by the host epidermal pouch wall. There were no host blood cells or other food resources in the pouch lumen. Since the host epidermis was intact and continuous, even in the vicinity of the oral region of the parasite, the copepod would not have access to the host blood in this state. However, the stomach (ampullary part of the mid gut) was filled with granular components, the majority of which were crystalloids that likely originated from fish erythrocyte hemoglobin. We supposed that the parasite drinks blood exuded from the lesion in the fish caused by copepod entry into the host tissue. Invasion of the parasite may elicit immune responses in the host, but there were no traces on the copepod of any cellular immune reactions, such as encapsulation. The array of minute protuberances on the copepod cuticle surface may be involved in avoidance of cell adhesion. After the lesion has healed, the copepod is enclosed in a tough epidermal pouch, in which it gradually digests the contents of its stomach and continues egg production.

Copepod (Crustacea) emergence from soils from everglades marshes with different hydroperiods

Science.gov (United States)

Loftus, W.F.; Reid, J.W.

2000-01-01

During a severe drought period in the winter and spring of 1989, we made three collections of dried marsh soils from freshwater sloughs in Everglades National Park, Florida, at sites characterized by either long or intermediate annual periods of flooding (hydroperiod). After rehydrating the soils in aquaria, we documented the temporal patterns of copepod emergence over two-week periods. The species richness of copepods in the rehydrated soils was lower than in pre-drought samples from the same slough sites. Only six of the 16 species recorded from the Everglades emerged in the aquarium tests. The long hydroperiod site had a slightly different assemblage and higher numbers of most species than the intermediate-hydroperiod sites. More individuals and species emerged from the early dry-season samples compared with samples taken later in the dry season. The harpacticoid, Cletocamptus deitersi, and the cyclopoid, Microcyclops rubellus, were abundant at most sites. The cyclopoids - Ectocyclops phaleratus, Homocyclops ater, and Paracyclops chiltoni - are new records for the Everglades. We infer that 1) only a subset of Everglades copepod species can survive drought by resting in soils; and that 2) survival ability over time differs by species.

Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

Science.gov (United States)

Garzke, Jessica; Hansen, Thomas; Ismar, Stefanie M H; Sommer, Ulrich

2016-01-01

Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5) and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA) and arachidonic acid (ARA) to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

Marine bioinvasions: Differences in tropical copepod communities between inside and outside a port

Science.gov (United States)

Soares, Marcelo de Oliveira; Campos, Carolina Coelho; Santos, Nívia Maria Oliveira; Barroso, Hortência de Sousa; Mota, Erika Maria Targino; Menezes, Maria Ozilea Bezerra de; Rossi, Sergio; Garcia, Tatiane Martins

2018-04-01

The difficulty of detecting non-indigenous species (NIS) in marine environments is an "invisible problem" in areas where plankton monitoring does not occur. In this study, we investigated the dominance of the NIS Temora turbinata and copepod community structure in two tropical marine habitats: inside an offshore port, which had turbid and calm waters, and outside the port, which was more hydrodynamic. Our study area was on the northeast coast of Brazil. We found 17 taxa of Copepoda, which were dominated by T. turbinata and the congener, T. stylifera. The high average density of the NIS (21.03 ind./m3) was in stark contrast with that of the native copepods (0.01-3.27 ind./m3). The NIS density was negatively correlated with the species richness and evenness of the native community, was significantly higher inside the port than outside, and was positively correlated with phytoplankton density. A multivariate analysis revealed that there was a significant difference in copepod community structure between inside and outside the port; outside the port, the community was more diverse, and the native T. stylifera was more abundant. We found that tropical copepod communities inside an offshore port have low diversity, and probably have little biotic resistance against NIS invasions. Our results, combined with those previously obtained, highlight the need to study the spatial distributions of NIS and native species in pelagic environments.

Linking climate change to community-level impacts on copepods via a new, trait-based model: Life-history and metabolic mechanisms compared

DEFF Research Database (Denmark)

Banas, Neil S.; Møller, Eva Friis; Nielsen, Torkel Gissel

2017-01-01

A new, trait-based copepod model ("Coltrane": Copepod Life-history Traits and Adaptation to Novel Environments) has been developed, drawing on past work on both optimal annual routines and trait-based plankton metacommunity models, in order to evaluate climate impacts on copepods via 1) phenology...... and physiology of local populations of C. finmarchicus, C. glacialis, and C. hyperboreus. Futhermore, the model replicates the observed range of stored lipid content of these copepod populations (30–60%, C. finmarchicus–C. hyperboreus), suggesting a means for linking changes in temperature and primary production...

Linking climate change to community-level impacts on copepods via a new, trait-based model: Life-history and metabolic mechanisms compared

DEFF Research Database (Denmark)

Banas, Neil S.; Møller, Eva Friis; Nielsen, Torkel Gissel

A new, trait-based copepod model ("Coltrane": Copepod Life-history Traits and Adaptation to Novel Environments) has been developed, drawing on past work on both optimal annual routines and trait-based plankton metacommunity models, in order to evaluate climate impacts on copepods via 1) phenology...... and physiology of local populations of C. finmarchicus, C. glacialis, and C. hyperboreus. Futhermore, the model replicates the observed range of stored lipid content of these copepod populations (30–60%, C. finmarchicus–C. hyperboreus), suggesting a means for linking changes in temperature and primary production...

The reproductive effort of Lepeophtheirus pectoralis (Copepoda: Caligidae): insights into the egg production strategy of parasitic copepods.

Science.gov (United States)

Frade, D G; Santos, M J; Cavaleiro, F I

2016-01-01

The reproductive effort of Lepeophtheirus pectoralis (Müller O. F., 1776), a caligid copepod, which is commonly found infecting the European flounder, Platichthys flesus (Linnaeus, 1758), is studied in detail for the first time. Seasonal variation in body dimensions and reproductive effort are analysed. Data for 120 ovigerous females, 30 from each season of the year, were considered in the analyses. Females were larger and produced a larger number of smaller eggs in winter, than during the summer. The relationship between egg number and egg size is similar to that recorded for other copepods exploiting fish hosts. Much of the recorded variation was also similar to that reported for a copepod parasitic on an invertebrate host, which suggests the possibility of a general trend in copepod reproduction. Overall, our results provide further support for the hypothesis that there is an alternation of summer and winter generations.

The toxicity of arsenic(III), chromium(VI) and zinc to groundwater copepods.

Science.gov (United States)

Hose, G C; Symington, K; Lott, M J; Lategan, M J

2016-09-01

Groundwater ecosystems globally are threatened by anthropogenic contamination, yet there are few ecotoxicological data using obligate groundwater biota on which to base risk assessments. Copepods are found inhabiting aquifers of different geologies around the world and so are a useful taxon for use in ecotoxicological studies of groundwater. The aim of this study was to test the sensitivity of obligate groundwater copepods to metal contaminants (arsenic(III), chromium(VI) and zinc) in groundwater in static 96 h, 14 days and 28 days exposure tests. The copepods were variably sensitive to As, Cr and Zn, with Cr being the most toxic across all taxa. No taxon was consistently most sensitive and there was no apparent relationship between the hardness, pH and organic carbon concentration of the diluent water and the sensitivity of biota. As expected, toxicity increased with exposure period and we encourage the use of longer exposure periods in future toxicity tests with groundwater organisms to reflect the greater exposure periods likely to be associated with groundwater contamination.

Bioaccumulation of sediment-associated fluoranthene in benthic copepods: uptake, elimination and biotransformation

International Nuclear Information System (INIS)

Lotufo, G.R.

1998-01-01

Most polycyclic aromatic hydrocarbons (PAHs) entering aquatic systems reside in sediments and in the storage lipids of the benthic biota. Massive amounts of PAHs reach estuarine systems and threaten their ecosystems. Copepods abound in the estuarine benthos, where they are an important component of food webs. The accumulation of sediment-associated [ 14 C]fluoranthene was examined in adult females of two species of sediment-dwelling copepods, Schizopera knabeni and Coullana sp., collected from a Louisiana salt marsh. Accumulation was measured throughout a short- (24 h) and a long-term (10-day) exposure to concentrations in the sediment ranging from 0 to 1652 nmol (g dry wt.) -1 . Fluoranthene apparent steady state body residue was reached very rapidly ( 14 C activity in the tissues following a 96-h sediment exposure in both species. Given that fluoranthene was taken up from spiked sediment very efficiently and reached steady-state levels in the tissues very rapidly, PAH-contaminated sediments may pose a risk for benthic copepods and their predators. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Effects of four synthetic musks on the life cycle of the harpacticoid copepod Nitocra spinipes

DEFF Research Database (Denmark)

Breitholtz, M.; Wollenberger, Leah; Dinan, L.

2003-01-01

A full life-cycle (:! 26 days exposure) toxicity test with the harpacticoid copepod Nitocra spinipes was used to study the effects of one nitro musk (musk ketone) as well as three polycyclic musks (Tonalide(TM), Celestolide(TM) and Galaxolide(TM)). A subchronic individual life-table endpoint......, the larval development rate, was recorded after 7-8 days exposure of juveniles and was significantly decreased in copepods exposed to sublethal concentrations of musk ketone, Celestolide(TM) and Galaxolide(TM). However, none of the Tonalide(TM) concentrations had any effect on larval development. The lowest...... significantly affected r(m) (***P copepods were dead at the end of the exposures. This shows that a sensitive individual life-table endpoint is protective over the population-level endpoint r(m). Though we think...

biological control agents of cyclopoid copepod, vector of ...

African Journals Online (AJOL)

In order to determine the predating capability of some indigenous fishes to Nigeria on cyclopoid copepods, the vector of Dracunculus medinensis, species of three genera of fishes were fled experimentally with Cyclops in the presence or absence of alternate food substances as described in the text. The study revealed that ...

Copepod colonization of organic and inorganic substrata at a deep-sea hydrothermal vent site on the Mid-Atlantic Ridge

Science.gov (United States)

Plum, Christoph; Pradillon, Florence; Fujiwara, Yoshihiro; Sarrazin, Jozée

2017-03-01

The few existing studies on deep-sea hydrothermal vent copepods indicate low connectivity with surrounding environments and reveal high endemism among vents. However, the finding of non-endemic copepod species in association with engineer species at different reduced ecosystems poses questions about the dispersal of copepods and the colonization of hydrothermal vents as well as their ecological connectivity. The objective of this study is to understand copepod colonization patterns at a hydrothermal vent site in response to environmental factors such as temperature and fluid flow as well as the presence of different types of substrata. To address this objective, an in situ experiment was deployed using both organic (woods, pig bones) and inorganic (slates) substrata along a gradient of hydrothermal activity at the Lucky Strike vent field (Eiffel Tower, Mid-Atlantic Ridge). The substrata were deployed in 2011 during the MoMARSAT cruise and were recovered after two years in 2013. Overall, copepod density showed significant differences between substrata types, but was similar among different hydrothermal activity regimes. Highest densities were observed on woods at sites with moderate or low fluid input, whereas bones were the most densely colonized substrata at the 2 sites with higher hydrothermal influence. Although differences in copepod diversity were not significant, the observed trends revealed overall increasing diversity with decreasing temperature and fluid input. Slates showed highest diversity compared to the organic substrata. Temperature and fluid input had a significant influence on copepod community composition, resulting in higher similarity among stations with relatively high and low fluid inputs, respectively. While vent-specialists such as dirivultids and the tegastid Smacigastes micheli dominated substrata at high vent activity, the experiment demonstrated increasing abundance and dominance of non-vent taxa with decreasing temperature and fluid

Copepod distribution and production in a Mid-Atlantic Ridge archipelago

Directory of Open Access Journals (Sweden)

PEDRO A.M.C. MELO

2014-12-01

Full Text Available The Saint Peter and Saint Paul Archipelago (SPSPA are located close to the Equator in the Atlantic Ocean. The aim of this study was to assess the spatial variations in the copepod community abundance, and the biomass and production patterns of the three most abundant calanoid species in the SPSPA. Plankton samples were collected with a 300 µm mesh size net along four transects (north, east, south and west of the SPSPA, with four stations plotted in each transect. All transects exhibited a tendency toward a decrease in copepod density with increasing distance from the SPSPA, statistically proved in the North. Density varied from 3.33 to 182.18 ind.m−3, and differences were also found between the first perimeter (first circular distance band and the others. The total biomass varied from 15.25 to 524.50 10−3 mg C m−3 and production from 1.19 to 22.04 10−3 mg C m−3d−1. The biomass and production of Undinula vulgaris (Dana, 1849, Acrocalanus longicornis Giesbrecht, 1888 and Calocalanus pavo (Dana, 1849 showed differences between some transects. A trend of declining biodiversity and production with increasing distance from archipelago was observed, suggesting that even small features like the SPSPA can affect the copepod community in tropical oligotrophic oceanic areas.

Community effectiveness of copepods for dengue vector control: systematic review.

Science.gov (United States)

Lazaro, A; Han, W W; Manrique-Saide, P; George, L; Velayudhan, R; Toledo, J; Runge Ranzinger, S; Horstick, O

2015-06-01

Vector control remains the only available method for primary prevention of dengue. Several interventions exist for dengue vector control, with limited evidence of their efficacy and community effectiveness. This systematic review compiles and analyses the existing global evidence for community effectiveness of copepods for dengue vector control. The systematic review follows the PRISMA statement, searching six relevant databases. Applying all inclusion and exclusion criteria, 11 articles were included. There is evidence that cyclopoid copepods (Mesocyclops spp.) could potentially be an effective vector control option, as shown in five community effectiveness studies in Vietnam. This includes long-term effectiveness for larval and adult control of Ae. aegypti, as well as dengue incidence. However, this success has so far not been replicated elsewhere (six studies, three community effectiveness studies--Costa Rica, Mexico and USA, and three studies analysing both efficacy and community effectiveness--Honduras, Laos and USA), probably due to community participation, environmental and/or biological factors. Judging by the quality of existing studies, there is a lack of good study design, data quality and appropriate statistics. There is limited evidence for the use of cyclopoid copepods as a single intervention. There are very few studies, and more are needed in other communities and environments. Clear best practice guidelines for the methodology of entomological studies should be developed. © 2015 John Wiley & Sons Ltd.

Combined Effects of Ocean Warming and Acidification on Copepod Abundance, Body Size and Fatty Acid Content.

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Jessica Garzke

Full Text Available Concerns about increasing atmospheric CO2 concentrations and global warming have initiated studies on the consequences of multiple-stressor interactions on marine organisms and ecosystems. We present a fully-crossed factorial mesocosm study and assess how warming and acidification affect the abundance, body size, and fatty acid composition of copepods as a measure of nutritional quality. The experimental set-up allowed us to determine whether the effects of warming and acidification act additively, synergistically, or antagonistically on the abundance, body size, and fatty acid content of copepods, a major group of lower level consumers in marine food webs. Copepodite (developmental stages 1-5 and nauplii abundance were antagonistically affected by warming and acidification. Higher temperature decreased copepodite and nauplii abundance, while acidification partially compensated for the temperature effect. The abundance of adult copepods was negatively affected by warming. The prosome length of copepods was significantly reduced by warming, and the interaction of warming and CO2 antagonistically affected prosome length. Fatty acid composition was also significantly affected by warming. The content of saturated fatty acids increased, and the ratios of the polyunsaturated essential fatty acids docosahexaenoic- (DHA and arachidonic acid (ARA to total fatty acid content increased with higher temperatures. Additionally, here was a significant additive interaction effect of both parameters on arachidonic acid. Our results indicate that in a future ocean scenario, acidification might partially counteract some observed effects of increased temperature on zooplankton, while adding to others. These may be results of a fertilizing effect on phytoplankton as a copepod food source. In summary, copepod populations will be more strongly affected by warming rather than by acidifying oceans, but ocean acidification effects can modify some temperature impacts.

Bioaccumulation of photoprotective compounds in copepods: environmental triggers and sources of intra-specific variability

Science.gov (United States)

Zagarese, H. E.; García, P.; Diéguez, M. D.; Ferraro, M. A.

2012-12-01

Ultraviolet radiation (UVR) and temperature are two globally important abiotic factors affecting freshwater ecosystems. Planktonic organisms have developed a battery of counteracting mechanisms to minimize the risk of being damaged by UVR, which respond to three basic principles: avoid, protect, repair. Copepods are among the most successful zooplankton groups. They are highly adaptable animals, capable of displaying flexible behaviors, physiologies, and life strategies. In particular, they are well equipped to cope with harmful UVR. Their arsenal includes vertical migration, accumulation of photoprotective compounds, and photorepair. The preference for a particular strategy is affected by a plethora of environmental (extrinsic) parameters, such as the existence of a depth refuge, the risk of visual predation, and temperature. Temperature modifies the environment (e.g. the lake thermal structure), and animal metabolism (e.g., swimming speed, bioaccumulation of photoprotective compounds). In addition, the relative weight of UVR-coping strategies is also influenced by the organism (intrinsic) characteristics (e.g., inter- and intra-specific variability). The UV absorbing compounds, mycosporine-like amino acids (MAAs), are widely distributed among freshwater copepods. Animals are unable to synthesize MAAs, and therefore depend on external sources for accumulating these compounds. Although copepods may acquire MAAs from their food, for the few centropagic species investigated so far, the main source of MAAs are microbial (most likely prokaryotic) organisms living in close association with the copepods. Boeckella gracilipes is a common centropagic copepod in Patagonian lakes. We suspected that its occurrence in different types of lakes, hydrologically unconnected, but within close geographical proximity, could have resulted in different microbial-copepod associations (i.e., different MAAs sources) that could translate into intra-specific differences in the accumulation

Some unsolved problems concerning copepods associated with marine invertebrates

NARCIS (Netherlands)

Gotto, R.V.

1990-01-01

Three unsolved problems relating to symbiotic copepods of marine invertebrates are discussed: 1. The whereabouts of the unknown male of the gill parasite of lobsters, Nicothoe astaci. 2. The occurrence of very large and apparently post-reproductive females in the annelidicolous Cyclorhiza megalova.

Sex-specific starvation tolerance of copepods with different foraging strategies

DEFF Research Database (Denmark)

Holm, Mark Wejlemann; Torres, Rocio Rodriguez; van Someren Gréve, Hans

2018-01-01

in starvation tolerance are not due to dissimilarities in lipid reserves. Gender differences in starvation tolerance can be partially explained by body size differences between sexes. This indicates a minor influence of mate-seeking behaviour on male starvation tolerance, likely due to reduced mate......Planktonic copepods have sexual dimorphism that can lead to differences in starvation tolerance between genders. Additionally, mating may be energetically costly and thus reduce starvation tolerance. We investigated the influence of sexual dimorphism and mating on starvation tolerance of copepods...... with different feeding behaviours: Oithona nana (ambusher), Temora longicornis (feeding-current feeder) and Centropages typicus (cruiser). Males of C. typicus and O. nana had a starvation tolerance lower than females, whereas T. longicornis had a similar starvation tolerance between genders. Only O. nana males...

Macroevolutionary patterns of sexual size dimorphism in copepods

Science.gov (United States)

Hirst, Andrew G.; Kiørboe, Thomas

2014-01-01

Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

Production and use of copepods in marine fish larviculture

DEFF Research Database (Denmark)

Støttrup, Josianne; Norsker, N.H.

1997-01-01

Batch and continuous cultures of the harpacticoid copepod Tisbe holothuriae have been run for numerous generations in the laboratory at the North Sea Centre and the harvested nauplii used as food in preliminary trials with first-feeding turbot (Psetta maxima syn. Scophthalmus maximus). The naupliar...

Water-body preferences of dominant calanoid copepod species in ...

African Journals Online (AJOL)

The distribution of five dominant calanoid copepods was related to different water masses in the Angola-Benguela Front system. Five water bodies were identified by principal component analysis, on the basis of abiotic parameters such as temperature, salinity, dissolved oxygen, phosphate, silicate, nitrate and nitrite.

Abundance, distribution, diversity and zoogeography of epipelagic copepods off the Egyptian Coast (Mediterranean Sea

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Howaida Y. Zakaria

2016-12-01

Full Text Available The abundance, distribution and diversity of epipelagic copepods were studied along the Egyptian Mediterranean Coast during April, August, 2008, February, 2009 and 2010. The geographical distribution and ecological affinities of the recorded species are presented in order to follow up the migrant species that recently entered in the study area. Copepoda was the most dominant zooplankton group, representing 74.14% of the total zooplankton counts. The annual averages of copepod abundance in the coastal, shelf and offshore zones were 699.3, 609.7 and 555.7 ind.m−3, respectively. Spring was the most productive and diversified season. 118 copepod species were identified in the study area; among them twelve species are recorded in the Mediterranean Sea for the first time and 41 species are new records in the Egyptian Mediterranean waters. The community was dominated by Oithona nana, Calocalanus pavo, Nannocalanus minor, Clausocalanus arcuicornis and Paracalanus parvus. The study area could be considered as a crossroad for migration process from Atlantic Ocean in the west and Indian Ocean via Red Sea and Suez Canal from the south. In addition, the maritime activities in the Mediterranean Sea may have contributed into the change of copepod diversity in the study area where some species could have come to the Egyptian Coast from other water systems via ballast water.

An analysis of how to improve production of copepods as live feed from tropical Taiwanese outdoor aquaculture ponds

DEFF Research Database (Denmark)

Blanda, Elisa; Drillet, Guillaume; Huang, Cheng-Chien

2017-01-01

. Lastly, this study shows evidence on the yearlong availability of copepods to the pond managers, which, based on standing stock and secondary productivity, easily could improve and intensify their harvest effort. Nauplii could be harvested all year long and adult copepods and copepodites could also...

Linking foraging strategies of marine calanoid copepods to patterns of nitrogen stable isotope signatures in a mesocosm study

DEFF Research Database (Denmark)

Sommer, Frank; Saage, A.; Santer, B.

2005-01-01

foraging mode and, further, with its nitrogen stable isotope signature (delta(15)N). This is because a more carnivorous diet may be expected to result in a higher delta(15)N. We tested this hypothesis in a mesocosm study using a density gradient (0 to 80 ind. 1(-1)) of calanoid copepods. We expected......The foraging modes of calanoid copepods differ in that stationary suspension-feeding is more easily detected by prey with strong escape responses (ciliates) than is 'cruising' or 'ambushing' feeding. Thus, the ability of a copepod to include heterotrophic prey in its diet may be associated with its...

Copepod feeding currents : flow patterns, filtration rates and energetics

NARCIS (Netherlands)

van Duren, L.A; Stamhuis, E.J; Videler, J.J

Particle image velocimetry was used to construct a quasi 3-dimensional image of the flow generated by the feeding appendages of the calanoid copepod Temora longicornis. By scanning layers of flow, detailed information was obtained on flow velocity and velocity gradients. The flow around feeding T.

Propulsion efficiency and imposed flow fields of a copepod jump

DEFF Research Database (Denmark)

Jiang, H.; Kiørboe, Thomas

2011-01-01

Pelagic copepods jump to relocate, to attack prey and to escape predators. However, there is a price to be paid for these jumps in terms of their energy costs and the hydrodynamic signals they generate to rheotactic predators. Using observed kinematics of various types of jumps, we computed...... the imposed flow fields and associated energetics of jumps by means of computational fluid dynamics simulations by modeling the copepod as a self-propelled body. The computational fluid dynamics simulation was validated by particle image velocimetry data. The flow field generated by a repositioning jump...... the flow structure. The flow field associated with an escape jump sequence also includes two dominant vortex structures: one leading wake vortex generated as a result of the first jump and one around the body, but between these two vortex structures is an elongated, long-lasting flow trail with flow...

Differences in the structure of copepod assemblages in four tropical estuaries: Importance of pollution and the estuary hydrodynamics.

Science.gov (United States)

Araujo, Adriana V; Dias, Cristina O; Bonecker, Sérgio L C

2017-02-15

We examined the relationship between pollution and structure of copepod assemblages in estuaries, using sampling standardization of salinity range to reduce the effects of "Estuarine Quality Paradox". Copepod assemblages were analyzed in four Southeast Brazilian estuaries with different water quality levels and different hydrodynamic characteristics. The pollution negatively impacted the descriptors of the assemblage structure. The distribution of structure of copepod assemblages also showed a main separation trend between the most polluted estuaries and those less polluted. Temperature was the main factor affecting the assemblage structuring in the four estuaries. This factor acted in synergism with the effects of pollution impact and physical characteristics of the estuaries on the structure of copepod assemblages, supporting the potential vulnerability of coastal environments due to nutrient enrichment associated with climate change. Our study demonstrated the importance of sampling standardization of the salinity range in estuaries for reliable analysis of pollution effects on biota. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of power-plant effects on zooplankton in the near field

International Nuclear Information System (INIS)

Polgar, T.T.; Bongers, L.H.; Krainak, G.M.

1976-01-01

With the use of a simple entrainment model that takes into account tidal recirculation, mixing, and once-through kill rate, theoretical expressions are derived for ratios of densities of live organisms at the intake of a power plant to densities in the far field. Experimental data on the abundances of dead and live stages of Eurytemora affinis and Acartia tonsa are used to compare to model results. A study of the entrainment of zooplankton near the intake of the Morgantown power plant and a concurrent study of the distribution of zooplankton in the Potomac River provided the biological data. Physical information was derived from extensive hydrographic measurements. Comparing experimental data with model predictions showed that radical depletions occurred in the naupliar stages near the plant site which cannot be accounted for by cooling-system or delayed entrainment mortalities. These near-field changes are attributed to avoidance reactions and to mortalities in the vicinity of the plant

Metabarcoding and metabolome analyses of copepod grazing reveal feeding preference and linkage to metabolite classes in dynamic microbial plankton communities.

Science.gov (United States)

Ray, Jessica L; Althammer, Julia; Skaar, Katrine S; Simonelli, Paolo; Larsen, Aud; Stoecker, Diane; Sazhin, Andrey; Ijaz, Umer Z; Quince, Christopher; Nejstgaard, Jens C; Frischer, Marc; Pohnert, Georg; Troedsson, Christofer

2016-11-01

In order to characterize copepod feeding in relation to microbial plankton community dynamics, we combined metabarcoding and metabolome analyses during a 22-day seawater mesocosm experiment. Nutrient amendment of mesocosms promoted the development of haptophyte (Phaeocystis pouchetii)- and diatom (Skeletonema marinoi)-dominated plankton communities in mesocosms, in which Calanus sp. copepods were incubated for 24 h in flow-through chambers to allow access to prey particles (<500 μm). Copepods and mesocosm water sampled six times spanning the experiment were analysed using metabarcoding, while intracellular metabolite profiles of mesocosm plankton communities were generated for all experimental days. Taxon-specific metabarcoding ratios (ratio of consumed prey to available prey in the surrounding seawater) revealed diverse and dynamic copepod feeding selection, with positive selection on large diatoms, heterotrophic nanoflagellates and fungi, while smaller phytoplankton, including P. pouchetii, were passively consumed or even negatively selected according to our indicator. Our analysis of the relationship between Calanus grazing ratios and intracellular metabolite profiles indicates the importance of carbohydrates and lipids in plankton succession and copepod-prey interactions. This molecular characterization of Calanus sp. grazing therefore provides new evidence for selective feeding in mixed plankton assemblages and corroborates previous findings that copepod grazing may be coupled to the developmental and metabolic stage of the entire prey community rather than to individual prey abundances. © 2016 John Wiley & Sons Ltd.

Trophic Cascading of Medusae on the Relationships between Copepods and Diatoms in a Subtropical Coastal Ecosystem

Directory of Open Access Journals (Sweden)

Jia-Lu Chung

2009-01-01

Full Text Available To investigate the spatial and temporal variation of phytoplankton and copepods, eight seasonal cruises (January 2005 ~ Oc to ber 2006 were conducted in a subtropical coast site that encom passed 19 sampling stations. The results in dicated that the temperature (18.4 - 29.7°C varied more than 10°C seasonally, while nutrient concentrations (ni trate: 0.4 - 6.3 mM, phosphate: 0.1 - 0.8 mM, and silicate 2.1 - 12.1 mM were in versely corre lated with temperature. Diatoms (2792 - 1602437 cells m-3 constituted > 90% of the phytoplankton as semblages and dinoflagellates (226 - 10029 cells m-3 represented only ~10% of the algaebiomass. Copepod abun dance (8 - 1031 ind. m-3 varied positively with that of diatom and tempeature. Therelative abundance of Temora spp. (1 - 712 ind. m-3 varied from 69% in summer; that of Paracalanus spp. (0.1 - 176 ind. m-3 were > 25% in spring and au tumn and Calanus spp. (0.5 - 24 ind. m-3 dom i nated in win ter and spring, but ac counted for only ~10% of the to tal copepods. Both di a tom den sity and copepod abun dance were positively correlated with temperature, indicating these two plank tongroups were left bot tom-up control. The copepod abun dance positively co-aried with diatoms in 2005, but not in 2006. Fur ther sea son-to-sea son analysis showed that the diatomvs. copepodratios changed positively only when the medusa abun dance changed greatly (> 40-fold between consecutive sea sons. During periods when the medusa abundance varied less than 10-fold between seasons, there is no relationship between the ratios and the medusa abun dance. This study suggests that the stability of the medusa abundance from season to season could be important in regulating the ecological linkage between diatoms and their predators ¡V copepods.

Temperature Affects the Use of Storage Fatty Acids as Energy Source in a Benthic Copepod (Platychelipus littoralis, Harpacticoida).

Science.gov (United States)

Werbrouck, Eva; Van Gansbeke, Dirk; Vanreusel, Ann; De Troch, Marleen

2016-01-01

The utilization of storage lipids and their associated fatty acids (FA) is an important means for organisms to cope with periods of food shortage, however, little is known about the dynamics and FA mobilization in benthic copepods (order Harpacticoida). Furthermore, lipid depletion and FA mobilization may depend on the ambient temperature. Therefore, we subjected the temperate copepod Platychelipus littoralis to several intervals (3, 6 and 14 days) of food deprivation, under two temperatures in the range of the normal habitat temperature (4, 15 °C) and under an elevated temperature (24 °C), and studied the changes in FA composition of storage and membrane lipids. Although bulk depletion of storage FA occurred after a few days of food deprivation under 4 °C and 15 °C, copepod survival remained high during the experiment, suggesting the catabolization of other energy sources. Ambient temperature affected both the degree of FA depletion and the FA mobilization. In particular, storage FA were more exhausted and FA mobilization was more selective under 15 °C compared with 4 °C. In contrast, depletion of storage FA was limited under an elevated temperature, potentially due to a switch to partial anaerobiosis. Food deprivation induced selective DHA retention in the copepod's membrane, under all temperatures. However, prolonged exposure to heat and nutritional stress eventually depleted DHA in the membranes, and potentially induced high copepod mortality. Storage lipids clearly played an important role in the short-term response of the copepod P. littoralis to food deprivation. However, under elevated temperature, the use of storage FA as an energy source is compromised.

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

International Nuclear Information System (INIS)

Michalec, François-Gaël; Holzner, Markus; Menu, Dominique; Hwang, Jiang-Shiou; Souissi, Sami

2013-01-01

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L −1 , cadmium at 45 ng L −1 and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L −1 all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

Energy Technology Data Exchange (ETDEWEB)

Michalec, François-Gaël [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Holzner, Markus [Institute of Environmental Engineering, ETH Zürich (Switzerland); Menu, Dominique [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); Hwang, Jiang-Shiou [National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Souissi, Sami, E-mail: sami.souissi@univ-lille1.fr [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France)

2013-08-15

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L{sup −1}, cadmium at 45 ng L{sup −1} and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L{sup −1} all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The

Effects of copepod size on fish growth: A model based on data for North Sea sandeel

DEFF Research Database (Denmark)

Deurs, Mikael van; Jørgensen, C.; Fiksen, Ø.

2015-01-01

In productive marine off-shore ecosystems, the flow of energy from zooplankton to large predators is channeled through a few species of short-lived, highly abundant schooling planktivorous fish. There are indications that these species respond to qualitative and phenological changes...... in the zooplankton. If so, the climate-induced alterations of the local copepod communities that we see in temperate and arctic regions may influence the energy flux in marine food chains. In order to investigate how different processes contribute to the relationship between copepod size and fish growth, we merged 2...... was the most important factor, followed by handling time limitation and prey energy content. These limitations became stronger with increasing fish length, showing that copepod size and energy content have a strong effect on the specific growth potential of these fish...

The chronic toxicity of molybdate to marine organisms. I. Generating reliable effects data

International Nuclear Information System (INIS)

Heijerick, D.G.; Regoli, L.; Stubblefield, W.

2012-01-01

A scientific research program was initiated by the International Molybdenum Association (IMOA) which addressed identified gaps in the environmental toxicity data for the molybdate ion (MoO 4 2− ). These gaps were previously identified during the preparation of EU-REACH-dossiers for different molybdenum compounds (European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances; EC, 2006). Evaluation of the open literature identified few reliable marine ecotoxicological data that could be used for deriving a Predicted No-Effect Concentration (PNEC) for the marine environment. Rather than calculating a PNEC marine using the assessment factor methodology on a combined freshwater/marine dataset, IMOA decided to generate sufficient reliable marine chronic data to permit derivation of a PNEC by means of the more scientifically robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Nine test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na 2 MoO 4 ·2H 2 O) according to published standard testing guidelines that are acceptable for a broad range of regulatory purposes. The selected test organisms were representative for typical marine trophic levels: micro-algae/diatom (Phaeodactylum tricornutum, Dunaliella tertiolecta), macro-alga (Ceramium tenuicorne), mysids (Americamysis bahia), copepod (Acartia tonsa), fish (Cyprinodon variegatus), echinoderms (Dendraster exentricus, Strongylocentrotus purpuratus) and molluscs (Mytilus edulis, Crassostrea gigas). Available NOEC/EC 10 levels ranged between 4.4 mg Mo/L (blue mussel M. edulis) and 1174 mg Mo/L (oyster C. gigas). Using all available reliable marine chronic effects data that are currently available, a HC 5,50% (median hazardous concentration affecting 5% of the species) of 5.74 (mg Mo)/L was derived with the statistical extrapolation approach, a value that can be used for national and

First report of ciliate (Protozoa) epibionts on deep-sea harpacticoid copepods

Science.gov (United States)

Sedlacek, Linda; Thistle, David; Fernandez-Leborans, Gregorio; Carman, Kevin R.; Barry, James P.

2013-08-01

We report the first observations of ciliate epibionts on deep-sea, benthic harpacticoid copepods. One ciliate epibiont species belonged to class Karyorelictea, one to subclass Suctoria, and one to subclass Peritrichia. Our samples came from the continental rise off central California (36.709°N, 123.523°W, 3607 m depth). We found that adult harpacticoids carried ciliate epibionts significantly more frequently than did subadult copepodids. The reason for the pattern is unknown, but it may involve differences between adults and subadult copepodids in size or in time spent swimming. We also found that the ciliate epibiont species occurred unusually frequently on the adults of two species of harpacticoid copepod; a third harpacticoid species just failed the significance test. When we ranked the 57 harpacticoid species in our samples in order of abundance, three species identified were, as a group, significantly more abundant than expected by chance if one assumes that the abundance of the group and the presence of ciliate epibionts on them were uncorrelated. High abundance may be among the reasons a harpacticoid species carries a ciliate epibiont species disproportionately frequently. For the combinations of harpacticoid species and ciliate epibiont species identified, we found one in which males and females differed significantly in the proportion that carried epibionts. Such a sex bias has also been reported for shallow-water, calanoid copepods.

Intraspecific differences in lipid content of calanoid copepods across fine-scale depth ranges within the photic layer.

Directory of Open Access Journals (Sweden)

Margarita Zarubin

Full Text Available Copepods are among the most abundant and diverse groups of mesozooplankton in the world's oceans. Each species has a certain depth range within which different individuals (of the same life stage and sex are found. Lipids are accumulated in many calanoid copepods for energy storage and reproduction. Lipid content in some species increases with depth, however studies so far focused mostly on temperate and high-latitude seasonal vertically migrating copepods and compared lipid contents among individuals either from coarse layers or between diapausing, deep-dwelling copepods and individuals found in the photic, near-surface layer. Here we examined whether lipid contents of individual calanoid copepods of the same species, life stage/sex differ between finer depth layers within the upper water column of subtropical and Arctic seas. A total of 6 calanoid species were collected from samples taken at precise depths within the photic layer in both cold eutrophic and warm oligotrophic environments using SCUBA diving, MOCNESS and Multinet. Measurements of lipid content were obtained from digitized photographs of the collected individuals. The results revealed significant differences in lipid content across depth differences as small as 12-15 meters for Mecynocera clausi C5 and Ctenocalanus vanus C5 (Red Sea, Clausocalanus furcatus males and two clausocalanid C5s (Mediterranean Sea, and Calanus glacialis C5 (Arctic. We suggest two possible explanations for the differences in lipid content with depth on such a fine scale: predator avoidance and buoyancy.

Rates of ingestion and their variability between individual calanoid copepods: Direct observations

Energy Technology Data Exchange (ETDEWEB)

Paffenhoefer, G.A.; Lewis, K.D. [Skidaway Inst. of Oceanography, Savannah, GA (United States); Bundy, M.H. [Skidaway Inst. of Oceanography, Savannah, GA (United States)]|[Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE); Metz, C. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany). Inst. fuer Fernerkundung (IFE)

1995-12-01

The goals of this study were to determine rates of ingestion and fecal pellet release, and their variability, for individual planktonic copepods over extended periods of time (>20 min). Ingestions and rejections of individual cells of the diatom Thalassiosira eccentrica by a adult females of the calanoid Paracalanus aculeatus were directly quantified by observing individual copepods continuously at cell concentrations ranging from 0.1 to 1.2 mm{sup 3} l{sup {minus}1}. Average ingestion rates increased with increasing food concentration, but were not significantly different between 0.3 and 1.0 mm{sup 3} l{sup {minus}1} (9.8 and 32.7 {mu}g Cl{sup {minus}1}) of T.eccentrica. Rates of cell rejections were low and similar at 0.1 and 0.3. but were significantly higher at 1.0 mm{sup 3} l{sup {minus}1}. The coefficients of variation for average ingestion rates of individual copepods hardly differed between food concentrations, ranging from 17 to 22%, and were close to those for average fecal pellet release intervals which ranged from 15 to 21%. A comparison between individuals at each food concentration found no significant differences at 1.0; at 0.1 and 0.3 mm{sup 3} l{sup {minus}1}, respectively, ingestion rates of four out of five females did not differ significantly from each other. Average intervals between fecal pellet releases were similar at 0.3 and 1.0 mm{sup 3} l{sup {minus}1}. Fecal pellet release intervals between individuals were significantly different at each food concentration; these significant differences were attributed to rather narrow ranges of pellet release intervals of each individual female. Potential sources/causes of variability in the sizes and rates of copepods in the ocean are evaluated.

Diel feeding rhythm of copepod size-fractions from Coliumo Bay, Central Chile

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Danilo Calliari

2001-12-01

Full Text Available The feeding behaviour of the size fractionated copepod assemblage was studied over a diel cycle in Coliumo Bay. In this shallow environment the photic layer reached the bottom and salinity, temperature, and food availability were fairly homogeneous throughout the water column. All four size-fractions (250-500 ?m, 500-1000 ?m, 1000-2000 ?m, >2000 ?m showed a period of high feeding activity during the night and low feeding activity during the day. The persistence of nocturnal feeding in the presence of high food concentration over the 24-h cycle is interpreted as a predator avoidance strategy: empty guts by day make copepods less conspicuous to their visual daytime predators.

Copepod reproduction is unaffected by diatom aldehydes or lipid composition

DEFF Research Database (Denmark)

Dutz, Jörg; Koski, Marja; Jonasdottir, Sigrun

2008-01-01

We investigated whether reduced reproductive success of copepods fed with diatoms was related to nutritional imbalances with regard to essential lipids or to the production of inhibitory aldehydes. In 10-d laboratory experiments, feeding, egg production, egg hatching success, and fecal pellet...

Population dynamics of calanoid copepods and the implications of their predation by clupeid fish in the Central Baltic Sea

DEFF Research Database (Denmark)

Möllmann, C.; Köster, Fritz

2002-01-01

. Additionally this study investigated the effect of predation by the major planktivorous fish species herring (Clupea harengus) and sprat (Sprattus sprattus) for the period 1977-1996 in the Gotland Basin (Central Baltic Sea). Examination of consumption by these fish species in relation to copepod production...... by sprat on CV/CVI of both copepod species in spring resulted in higher copepod mortality rates. In consequence, based on these results we suggest that the increase in the sprat stock since the late 1980s contributed to a decline of P. elongatus, and additionally prevented an even more pronounced...

How much crude oil can zooplankton ingest? Estimating the quantity of dispersed crude oil defecated by planktonic copepods

DEFF Research Database (Denmark)

Almeda, Rodrigo; Connelly, Tara L.; Buskey, Edward J.

2016-01-01

% of the analyzed fecal pellets from three species of copepods and a natural copepod assemblage exposed for 48 h to physically or chemically dispersed light crude oil contained crude oil droplets. Crude oil droplets inside fecal pellets were smaller (median diameter: 2.4-3.5 mu m) than droplets in the physically...

A cost-effectiveness analysis of live feeds in juvenile turbot Scophthalmus maximus (Linnaeus, 1758) farming: copepods versus Artemiapepods versus Artemiacopepods versus Artemiacopepods versus Artemia

DEFF Research Database (Denmark)

Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max

2016-01-01

The biological benefits of copepods as live feed for marine finfish larvae have already been well established in the literature. Copepods have better biochemical compositions that improve growth, reduce malpigmentations and allow successful farming of ‘new’ marine finfish species. However...... items (copepods and Artemia) in juvenile turbot farming. Unit cost of production and profit are compared between the two feeding regimes using a unique data set from an existing turbot fry production facility in Denmark. The result reveals that copepods are not only biochemically superior...... but they are also economically a cost-effective alternative. Thus, a commercial use of copepods will significantly reduce the production costs for turbot. Furthermore, the unexploited economic potential can be utilized for the successful farming of other high-valued marine finfish species such as tuna, flounders...

Importance and nutritional value of large ciliates for the reproduction of Acartia clausi during the post spring-bloom period in the North Sea

DEFF Research Database (Denmark)

Dutz, Jörg; Peters, J.

2008-01-01

enriched with large prey (> 20 mu m). The mineral (C, N) and lipid contents of the food suspensions were determined for size-fractionated samples to characterize the nutritional composition of prey. Large oligotrich ciliates and Strobiliidae dominated the seston biomass. Ciliates, particularly......Shipboard experiments were performed to examine the qualitative importance of large marine microzooplankton for the reproduction of Acartia clausi in the North Sea. Feeding and egg production were compared in 2 treatments in which females were fed natural seston or natural seston selectively...

Estructura genética del copépodo Acartia lilljeborgii en la costa del estado de Yucatán, México

OpenAIRE

Jorge Tello-Cetina; Lucia Gómez-Victoria; Roberto Zamora-Bustillos; Gerardo Rivera-Muñoz; Sara Solis-Pereira; Herbert Loria-Sunza

2013-01-01

Se determinó la estructura genética poblacional y sus implicancias dentro de la cadena trófica del copépodo Acartia lilljeborgii en la costa de Yucatán, mediante el uso de isoenzimas y su posterior determinación por electroforesis. Nueve sistemas se expresaron con un máximo de 30 loci. El polimorfismo y heterocigosis de las poblaciones estudiadas, al ser comparados con otras especies de copépodos, resultaron ser bajos y de los cuatro loci que presentaron variación, solo los loci EST2 y PGM1 s...

Evaluating pyrene toxicity on Arctic key copepod species Calanus hyperboreus

DEFF Research Database (Denmark)

Nørregaard, Rasmus Dyrmose; Nielsen, Torkel Gissel; Friis Møller, Eva

2014-01-01

was unaffected. The hatching success was also unaffected, although the total reproductive output was reduced with increased pyrene concentrations. Accumulation of pyrene in the copepods was higher in feeding than starving females and only trace amounts of the phase I metabolite 1-hydroxypyrene, were found...

The mitochondrial genomes of Amphiascoides atopus and Schizopera knabeni (Harpacticoida: Miraciidae) reveal similarities between the copepod orders Harpacticoida and Poecilostomatoida.

Science.gov (United States)

Easton, Erin E; Darrow, Emily M; Spears, Trisha; Thistle, David

2014-03-15

Members of subclass Copepoda are abundant, diverse, and-as a result of their variety of ecological roles in marine and freshwater environments-important, but their phylogenetic interrelationships are unclear. Recent studies of arthropods have used gene arrangements in the mitochondrial (mt) genome to infer phylogenies, but for copepods, only seven complete mt genomes have been published. These data revealed several within-order and few among-order similarities. To increase the data available for comparisons, we sequenced the complete mt genome (13,831base pairs) of Amphiascoides atopus and 10,649base pairs of the mt genome of Schizopera knabeni (both in the family Miraciidae of the order Harpacticoida). Comparison of our data to those for Tigriopus japonicus (family Harpacticidae, order Harpacticoida) revealed similarities in gene arrangement among these three species that were consistent with those found within and among families of other copepod orders. Comparison of the mt genomes of our species with those known from other copepod orders revealed the arrangement of mt genes of our Harpacticoida species to be more similar to that of Sinergasilus polycolpus (order Poecilostomatoida) than to that of T. japonicus. The similarities between S. polycolpus and our species are the first to be noted across the boundaries of copepod orders and support the possibility that mt-gene arrangement might be used to infer copepod phylogenies. We also found that our two species had extremely truncated transfer RNAs and that gene overlaps occurred much more frequently than has been reported for other copepod mt genomes. Published by Elsevier B.V.

Planktivorous feeding in calm and turbulent environments, with emphasis on copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Saiz, E.

1995-01-01

Turbulence may enhance contact rates between planktonic predators and their prey. We formulate simple and general models of prey encounter rates, taking into account the behaviours and motility patterns of both prey and predator as well as turbulent fluid motion. Using these models we determine...... the levels of turbulence (as dissipation rate) at which ambient fluid motion is important in enhancing prey encounter rates for various types of predators (e.g, ambush and cruise predators, suspension feeders). Generally, turbulence has the largest effect on prey encounters for predators with low motility...... and long reaction distances. Also, turbulence is most important for meso-sized (mm to cm) predators and insignificant for smaller and larger predators. The effect of turbulence on copepods is specifically examined. For copepods that establish feeding currents, turbulence is of minor importance; for ambush...

Sticholonche zanclea (Protozoa, Actinopoda in fecal pellets of copepods and Euphausia sp. in Brazilian coastal waters

Directory of Open Access Journals (Sweden)

E. M. Eskinazi-Sant'Anna

Full Text Available Fecal pellets produced by mesozooplanktonic copepods (Centropages velificatus and Paracalanus parvus and macrozooplanktonic Euphausiacea (Euphausia sp. were examined using scanning electron microscopy. Fragments of the protozoan Sticholonche zanclea were found in both copepod and in Euphausia sp. fecal pellets, even when the abundance of the protozoan in the water was low. The results suggest that S. zanclea is an important food resource for different trophic levels, including meso- and macrozooplankton, in Brazilian coastal waters.

Distribution of copepods from the polluted and unpolluted regions off Bombay

Digital Repository Service at National Institute of Oceanography (India)

Gajbhiye, S.N.; JiyalalRam, M.J.; Desai, B.N.

Distribution and abundance of copepods in the nearshore waters off Bombay were studied at 4 fixed sampling sites during October 1977 to December 1978.The stations Mahim and Thana received domestic and industrial waste while the stations of Versova...

Role of small-sized copepods in the lipid-driven Arctic marine food web

Science.gov (United States)

Daase, M.; Boissonnot, L.; Graeve, M.; Søreide, J.; Niehoff, B.

2016-02-01

Despite of the low individual biomass of small-sized copepods such as the calanoid Pseudocalanus minutus and the cyclopoid Oithona similis, they are extremely numerous which make them an important trophic component in Arctic marine ecosystems. Due to the strong seasonality in light and thus primary production and food availability, the accumulation of lipid reserves is a key feature in Arctic marine ecosystems. However, very few studies exist on the lipid biochemistry of small copepods such as P. minutus and O. similis. In order to investigate the importance of these species in terms of transfer of lipids from primary production to higher trophic levels, feeding experiments were conducted, based on animals from Billefjorden, a high-Arctic fjord in Svalbard, Norway. A mixture of 13C labeled flagellates and diatoms was fed to the animals and the transfer and assimilation of lipid carbon, fatty acids and fatty alcohols was analyzed with gas chromatography-IRMS technique (CSIA). The results revealed that both species were incorporating dietary lipids in high quantities. The highest accumulation occurred in P. minutus in which 54.4% of the lipids were exchanged after 21 days, whereas 9.4% were assimilated in O. similis. Hence, at least this amount of carbon was used for metabolism and replaced by feeding. The lipid composition of the copepods did not reflect exactly the algal lipids, and differed between P. minutus and O. similis. Our results suggested intrinsic preferences in the accumulation of particular fatty acids, probably related to species-specific body requirements. This emphasizes the importance of also food quality in Arctic marine systems. Due to the relatively high lipid turnover rates in particularly in P. minutus, also small copepods are important drivers of the lipid-driven Arctic marine food web.

Vertical distribution and structure of copepod (Arthropoda: Copepoda assemblages in two different seasons down to 1,200 m in the tropical Southwestern Atlantic

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Cristina de Oliveira Dias

2018-05-01

Full Text Available ABSTRACT The vertical distribution of copepod assemblages, ascertained from the surface down to 1,200 m, was investigated during two sampling periods (rainy and dry seasons, at four depths, in the oligotrophic waters of the southwestern Atlantic Ocean. Total density, diversity, and richness differed among sampling depths. Copepod density decreased with depth in the two sampling periods, with a maximum at 1 m and a slight decrease at 800 m. Higher diversities were observed at 250 m and 1,200 m during the rainy season and at 1 m and 1,200 m during the dry season. The maximum number of species was found at 1,200 m during the rainy season and at 1 m during the dry season. Various copepod assemblages were delimited in the water column in the two sampling periods. The deeper copepod assemblages occupied a wider range of depths. Salinity and temperature influenced the structure of copepod assemblages and reflected the hydrographic characteristics of the water masses in the region. Candacia pachydactyla (Dana, 1849, Scolecithrix danae (Lubbock, 1856, and Agetus limbatus (Brady, 1883 were the indicator species found at 1 m. The effects of different environmental factors on the copepod assemblages suggest that these consortia occupy distinct niches in the ocean.

Differential gene expression profile of the calanoid copepod, Pseudodiaptomus annandalei, in response to nickel exposure.

Science.gov (United States)

Jiang, Jie-Lan; Wang, Gui-Zhong; Mao, Ming-Guang; Wang, Ke-Jian; Li, Shao-Jing; Zeng, Chao-Shu

2013-03-01

To better understand the underlying mechanisms of reactions of copepods exposed to elevated level of nickel, the suppression subtractive hybridization (SSH) was used to elucidate the response of the copepod Pseudodiaptomus annandalei to nickel exposure at the gene level. P. annandale is one of a few copepod species that can be cultured relatively easy under laboratory condition, and it is considered to be a potential model species for toxicity study. In the present study, P. annandalei were exposed to nickel at a concentration of 8.86 mgL(-1) for 24h, after which the RNA was prepared for SSH using unexposed P. annandalei as drivers. A total of 474 clones on the middle scale in the SSH library were sequenced. Among these genes, 129 potential functional genes were recognized based on the BLAST searches in NCBI and Uniprot databases. These genes were then categorized into nine groups in association with different biological processes using AmiGO against the Gene Ontology database. Of the 129 genes, 127 translatable DNA sequences were predicted to be proteins, and the putative amino acid sequences were searched for conserved domains (CD) and proteins using the CD-Search service and BLASTp. Among 129 genes, 119 (92.2%) were annotated to be involved in different biological processes, while 10 genes (7.8%) were classified as an unknown-function gene group. To further confirm the up-regulation of differentially expressed genes, the quantitative real time PCR were performed to test eight randomly selected genes, in which five of them, i.e. α-tubulin, ribosomal protein L13, ferritin, separase and Myohemerythrin-1, exhibited clear up-regulation after nickel exposure. In addition, MnSOD was further studied for the differential expression pattern after nickel exposure and the results showed that MnSOD had a time- and dose-dependent expression pattern in the copepod after nickel exposure. To the best of our knowledge, this is the first attempt to investigate the toxicity

Copepod grazing and their impact on phytoplankton standing stock and production in a tropical coastal water during the different seasons.

Science.gov (United States)

Jagadeesan, L; Jyothibabu, R; Arunpandi, N; Parthasarathi, S

2017-03-01

The grazing rate of copepods on the total and size-fractionated phytoplankton biomass in a coastal environment (off Kochi, southwest coast of India) were measured during pre-monsoon (PRM), peak southwest monsoon (PKSWM), late southwest monsoon (LSWM) and post-southwest monsoon (PSWM). The phytoplankton standing stock (chlorophyll a-Chl. a) and growth rate (GR) were less during the PRM (Chl. a 0.58 mg m -3 ; GR 0.23 ± 0.02) and PSWM (Chl. a 0.89 mg m -3 ; GR 0.30 ± 0.05) compared to PKSWM (Chl. a 6.67 mg m -3 ; GR 0.43 ± 0.02) and LSWM (Chl. a 4.09 mg m -3 ; GR 0.40 ± 0.04). The microplankton contribution to the total Chl. a was significant during the PKSWM (41.83%) and LSWM (45.72%). Copepod density was lesser during the PRM (1354 No m -3 ) and PSWM (1606 No m -3 ) than during PKSWM and LSWM (4571 and 3432 No m -3 , respectively). Seasonal changes in phytoplankton biomass, phytoplankton size structure, and copepod community were closely related to the hydrographical transformations in the study domain. Dominant calanoid copepods in the study region ingested 8.4 to 14.2% of their daily ration from phytoplankton during the PRM and PSWM, which increased to >50% during the PKSWM and LSWM. The cyclopoid Oithona similis was abundant during the PKSWM, ingesting only 21% of their daily ration from phytoplankton. Temporal variation in the phytoplankton biomass and copepod species composition caused differences in community level top-down control. The copepod community ingestion on phytoplankton was high during the LSWM (18,583 μg C m -3 d -1 ), followed by PKSWM (9050 μg C m -3 d -1 ), PSWM (1813 μg C m -3 d -1 ), and PRM (946 μg C m -3 d -1 ). During the low Chl. a period (PRM and PSWM), dominant calanoid copepods showed a positive selectivity for the micro- and nano-phytoplankton size fractions, whereas during the high Chl. a period (PKSWM and LSWM), they showed a positive selection for nano-phytoplankton fractions. Irrespective

Feeding, growth, and food conversion of the marine planktonic copepod Calanus helgolandicus

Energy Technology Data Exchange (ETDEWEB)

Paffenhoefer, G.A.

1976-01-01

Food intake, growth rate, and food conversion of nauplii, copepodids, and adult females of Calanus helgolandicus were investigated experimentally at 15/sup 0/C. The diatom Lauderia borealis and the dinoflagellates Gonyaulax polyedra, Gymnodinium splendens, and Prorocentrum micans were offered separately as food at concentrations ranging from 41 to 101 ..mu..g C liter/sup -1/. Amounts of food ingested differed with concentration and species. Daily exponential growth rates were highest for nauplii and young copepodids (k = 0.29 to 0.41) and decreased gradually with increasing age of the copepods to k = 0.02. Gross growth efficiency changed during the different juvenile life periods of the copepod with maximum values for the period CdI to CIII. Feeding on L. borealis at lower food concentrations resulted in an increase in gross growth efficiency. (auth)

Reading the copepod personal ads : increasing encounter probability with hydromechanical signals

NARCIS (Netherlands)

van Duren, LA; Stamhuis, EJ; Videler, JJ

1998-01-01

Females of the calanoid copepod Temora longicornis react to chemical exudates of male conspecifics with little hops, quite distinct from their normal smooth uniform swimming motion. These hops possibly serve to create a hydrodynamical signal in the surrounding water, to increase encounter

Chlorine toxicity to copepods: implications in the context of zooplankton entrainment in power plants

International Nuclear Information System (INIS)

Ershath, M.; Altaff, K.; Sriyutha Murthy, P.; Venugopalan, V.P.

2008-01-01

Full text: Experiments were conducted to assess the effects of chlorine on zooplankton, such as those entrained into cooling water circuits of power stations. Three copepod groups (Calanoida, Cyclopoida and Harpacticoida) and copepod naupliar stages were chosen for the study. Percentage mortality of the different groups of copepods and the naupliar stages was assessed after 5, 15, 30, 45 and 60 min of exposure to chlorine residuals of 0.2, 0.5, 0.8 and 1.0 mg/1. Mortality increased with increase in exposure time and concentration of the biocide. Calanoids were relatively more tolerant to chlorine compared to the other groups. Chlorine toxicity may be classified (from more tolerant to less tolerant) as calanoids > cyclopoida > harpacticoids > naupliar stages. Continuous chlorination (with total chlorine residuals of 0.1 - 0.3 mg/l at the discharge) is the general practice adopted in tropical power stations. Considering this, results of the present study indicate and expected percentage mortality of the different groups as: calanoids - 7.9%, cyclopoids - 11.1%, harpacticoids - 10.2% and naupliar stages - 21.6%. However, the data need to be verified under actual plant conditions. (author)

Prevalence of the parasitic copepod Haemobaphes intermedius on juvenile buffalo sculpins from Washington State

Science.gov (United States)

Halpenny, C.M.; Kocan, R.M.; Hershberger, P.K.

2004-01-01

The parasitic copepod, Haemobaphes intermedius, was detected in 62% of juvenile buffalo sculpins Enophrys bison, a previously unreported host, from the San Juan Islands archipelago in Washington State. Most infestations were characterized by the presence of a single female copepod infestations with multiple H. intermedius occurred either unilaterally or bilaterally in 29% of parasitized individuals. Impaired condition of parasitized hosts was indicated by significantly lower total lengths and weights (34.9 mm; 1.6 g) than in unparasitized cohorts (38.9 mm; 2.1 g). Host specificity was indicated by the failure to detect H. intermedius in 43 sympatric great sculpins Myoxocephalus polyacanthocephalus from the same location.

First record of small tropical calanoid copepod Parvocalanus crassirostris (Copepoda, Calanoida, Paracalanidae in the Adriatic Sea

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O. VIDJAK

2016-09-01

Full Text Available In December 2014 the adult females and copepodites of alien paracalanid copepod Parvocalanus crassirostris were identified in the Central Adriatic port of Šibenik. The most probable transmission vector for this small copepod were ballast waters from the cargo ships that are regularly discharged at these locations. This paper is focused on P. crassirostris morphology and the state of population in the port of Šibenik. The possible path of introduction of Parvocalanus crassirostris into the Adriatic Sea is also discussed.

Ocean acidification impact on copepod swimming and mating behavior: consequences for population dynamics

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Seuront, L.

2010-12-01

There is now ample evidence that ocean acidification caused by the uptake of additional carbon dioxide from the atmosphere at the ocean surface will severely impact on marine ecosystem structure and function. To date, most research effort has focused on the impact of ocean acidification on calcifying marine organisms. These include the dissolution of calcifying plankton, reduced growth and shell thickness in gastropods and echinoderms and declining growth of reef-building corals. The effects of increasing the partial pressure in carbon dioxide and decreasing carbonate concentrations on various aspects of phytoplankton biology and ecology have received some attention. It has also recently been shown that the ability of fish larvae to discriminate between the olfactory cues of different habitat types at settlement and to detect predator olfactory cues are impaired at the level of ocean acidification predicted to occur around 2100 on a business-as-usual scenario of CO2 emissions. Average ocean pH has decreased by 0.1 units since the pre-industrial times, and it is predicted to decline another 0.3-0.4 units by 2100, which nearly corresponds to a doubling PCO2. In addition, some locations are expected to exhibit an even greater than predicted rate of decline. In this context, understanding the direct and indirect links between ocean acidification and the mortality of marine species is critical, especially for minute planktonic organisms such as copepods at the base of the ocean food chains. In this context, this work tested if ocean acidification could affect copepod swimming behavior, and subsequently affect, and ultimately disrupt, the ability of male copepods to detect and follow the pheromone plume produced by conspecific females. To ensure the generality and the ecological relevance of the present work, the species used for the experimentation are two of the most common zooplankton species found in estuarine and coastal waters of the Northern Hemisphere, the

Acute toxicity, uptake and accumulation kinetics of nickel in an invasive copepod species: Pseudodiaptomus marinus.

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Tlili, Sofiène; Ovaert, Julien; Souissi, Anissa; Ouddane, Baghdad; Souissi, Sami

2016-02-01

Pseudodiaptomus marinus is a marine calanoid copepod originating of the Indo-Pacific region, who has successfully colonized new areas and it was recently observed in the European side of the Mediterranean Sea as well as in the North Sea. Actually, many questions were posed about the invasive capacity of this copepod in several non-native ecosystems. In this context, the main aim of this study was to investigate the tolerance and the bioaccumulation of metallic stress in the invasive copepod P. marinus successfully maintained in mass culture at laboratory conditions since 2 years. In order to study the metallic tolerance levels of P. marinus, an emergent trace metal, the nickel, was chosen. First, lethal concentrations determination experiments were done for 24, 48, 72 and 96 h in order to calculated LC50% but also to select a relevant ecological value for the suite of experiments. Then, three types of experiments, using a single concentration of nickel (correspond the 1/3 of 96 h-LC50%) was carried in order to study the toxico-kinetics of nickel in P. marinus. Concerning lethal concentrations, we observed that P. marinus was in the same range of sensitivity compared to other calanoid copepods exposed to nickel in the same standardized experimental conditions. Results showed that the uptake of nickel in P. marinus depends from the pathways of entrance (water of food), but also that Isochrysis galbana, used as a food source, has an important bioaccumulation capacity and a rapid uptake of nickel. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low fertilization rates in a pelagic copepod caused by sexual selection?

DEFF Research Database (Denmark)

Ceballos, Sara; Sichlau, Mie Hylstofte; Heuschele, Jan

2014-01-01

We studied female fertilization status in North Sea summer populations and laboratory cultures of the marine copepod Temora longicornis and found fractions of fertilized females in both field and laboratory populations that were much smaller (<50%) than predicted by a theoretical model that assum...

Effects of environmental and water quality parameters on the functioning of copepod assemblages in tropical estuaries

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Araujo, Adriana V.; Dias, Cristina O.; Bonecker, Sérgio L. C.

2017-07-01

We examined changes in the functioning of copepod assemblages with increasing pollution in estuaries, using sampling standardization of the salinity range to enable comparisons. Copepod assemblages were analyzed in four southeast Brazilian estuaries with different water quality levels and hydrodynamic characteristics over two years. We obtained mesozooplankton samples together with environmental and water quality parameters in the estuaries, every two months under predetermined salinities ranging from 15 to 25. The values of parameters, except species size, associated with the functioning of the copepod assemblages (biomass, productivity, and turnover rate) did not differ among estuaries. However, in the more polluted estuaries, the biomass and productivity of copepod assemblages of mesozooplankton were negatively correlated with concentration of pollution indicator parameters. Conversely, in the less polluted estuaries some degree of enrichment still seems to increase the system biomass and productivity, as these parameters were inversely related to indicators of improved water quality. The pollution level of estuaries distorted the relationship between temperature and the efficiency of converting energy to organic matter. In the less polluted estuaries, the relationship between turnover rate and temperature was over 70%, while in the most polluted estuaries, this relationship was only approximately 50%. Our results demonstrated that the functioning of assemblages in the estuaries was affected differently by increasing pollution depending on the water quality level of the system. Thus, investigating the functioning of assemblages can be a useful tool for the analysis of estuarine conditions.

Distribution of calanoid copepods in the Arabian sea and Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Stephen, R.

The distribution of calanoid copepods from the northern Arabian Sea and Bay of Bengal is discussed in relation to thermocline. The inshore offshore zonation of a neritic, shelf an oceanic communities was traced based on the species composition...

De novo assembly and annotation of the Antarctic copepod (Tigriopus kingsejongensis) transcriptome.

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Kim, Hui-Su; Lee, Bo-Young; Han, Jeonghoon; Lee, Young Hwan; Min, Gi-Sik; Kim, Sanghee; Lee, Jae-Seong

2016-08-01

The whole transcriptome of the Antarctic copepod (Tigriopus kingsejongensis) was sequenced using Illumina RNA-seq. De novo assembly was performed with 64,785,098 raw reads using Trinity, which assembled into 81,653 contigs. TransDecoder found 38,250 candidate coding contigs which showed homology to other species by BLAST analysis. Functional gene annotation was performed by Gene Ontology (GO), InterProScan, and KEGG pathway analyses. Finally, we identified a number of expressed gene catalog for T. kingsejongensis that is a useful model animal for gene information-based polar research to uncover molecular mechanisms of environmental adaptation on harsh environments. In particular, we observed highly developing lipid metabolism in T. kingsejongensis directly compared to those of the Far East Pacific coast copepod Tigriopus japonicus at the transcriptome level. Copyright © 2016 Elsevier B.V. All rights reserved.

How coastal upwelling influences spatial patterns of size-structured diversity of copepods off central-southern Chile (summer 2009)

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Hidalgo, Pamela; Escribano, Ruben; Fuentes, Marcelo; Jorquera, Erika; Vergara, Odette

2012-01-01

This study assessed the structure of the copepod community in the upper 200 m of the coastal upwelling region off central-southern Chile in late summer 2009. Vertically stratified zooplankton samples and hydrographic variables were obtained from 42 stations over the continental shelf and oceanic areas. The survey took place during active upwelling, reflected by a cold upwelling plume extending out to 150 km offshore. A total of 62 copepod species were found. Of these, Oithona similis and Paracalanusindicus accounted for ca. 60% of the whole community. Species richness ( R) and the Shannon-Wiener diversity index ( H‧) were estimated, and the latter was additionally modified to incorporate the effect of copepod size on diversity ( H‧ s). Samples were analyzed for two depth strata (0-50, 50-200 m) and for day vs. night conditions. Significant effects of day vs. night and strata on R, H‧ and H‧ s indicated that diel vertical migration between these two layers was an important source of variation in the zooplankton community. H‧ s seemed to represent copepod diversity better than R and H‧ over the spatial scale. H‧ s was also closely linked to colder upwelled water and the depth of the oxygen minimum zone following a principal component analysis. A positive relationship was even detected between depth of the oxygen minimum zone and H‧ s when strata and day/night effects were excluded. Our findings suggested that the coastal upwelling process could be an important driver of copepod diversity in this region. Upwelling leads to changes in the depth of the oxygen minimum zone and these changes impact the community composition due to species-dependent tolerances to low oxygen water.

Electrophoretic protein profiles of mid-sized copepod Calanoides patagoniensis steadily fed bloom-forming diatoms

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Victor M Aguilera

2015-09-01

Full Text Available Recent field and experimental evidence collected in the southern upwelling region off Concepción (36°5'S, 73°3'W showed an abrupt reduction (<72 h in the egg production rates (EPR of copepods when they were fed steadily and solely with the local bloom-forming diatom Thalassiosira rotula. Because diatoms were biochemically similar to dinoflagellate Prorocentrum minimum, a diet which supported higher reproductive outcomes, the fecundity reduction observed in copepod females fed with the diatom may have obeyed to post-ingestive processes, giving rise to resources reallocation. This hypothesis was tested by comparing feeding (clearance and ingestion rates, reproduction (EPR and hatching success and the structure of protein profiles (i.e., number and intensity of electrophoretic bands of copepods (adults and eggs incubated during 96 h with the two food conditions. The structure of protein profiles included molecular sizes that were calculated from the relative mobility of protein standards against the logarithm of their molecular sizes. After assessing the experimental conditions, feeding decreased over time for those females fed with T. rotula, while reproduction was higher in females fed with P. minimum. Electrophoretic profiles resulted similar mostly at a banding region of 100 to 89-kDa, while they showed partial differences around the region of 56-kDa band, especially in those females fed and eggs produced with T. rotula. Due to reproductive volume was impacted while larvae viability, a physiological processes with specific and high nutritional requirements, was independent on food type; post-ingestive processes, such as expression of stress-related proteins deviating resources to metabolic processes others than reproduction, are discussed under framework of nutritional-toxic mechanisms mediating copepod-diatoms relationships in productive upwelling areas.

Fitness costs and benefits of ultraviolet radiation exposure in marine pelagic copepods

DEFF Research Database (Denmark)

Hylander, Samuel; Grenvald, Julie Cornelius; Kiørboe, Thomas

2014-01-01

Life-history theory predicts that organisms should allocate energy throughout their life such that they maximize their fitness. Copepod zooplankton are known to accumulate sunscreens (so-called mycosporine-like amino acids, MAAs) and antioxidant carotenoids to mitigate negative effects...

The parasitic copepod Lernaeocera branchialis negatively affects cardiorespiratory function in Gadus morhua

DEFF Research Database (Denmark)

Behrens, Jane W.; Seth, H.; Axelsson, M.

2014-01-01

The parasitic copepod Lernaeocera branchialis had a negative effect on cardiorespiratory function in Atlantic cod Gadus morhua such that it caused pronounced cardiac dysfunction with irregular rhythm and reduced stroke amplitude compared with uninfected fish. In addition, parasite infection...

On the occurrence of endoparasites from copepods of the west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Santhakumari, V.

Occurrence of endoparasitic dinoflagellates belonging to the genera, Blastodinium, parasitizing the coelomic cavity of their host, copepods was investigated. Infection by these species seems to be harmful to the host. Parasitized individuals showed...

Annual egg production rates of calanoid copepod species on the continental shelf of the Eastern Tropical Pacific off Mexico

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Kozak, Eva R.; Franco-Gordo, Carmen; Palomares-García, Ricardo; Gómez-Gutiérrez, Jaime; Suárez-Morales, Eduardo

2017-01-01

We provide the first estimations of calanoid copepod egg production rates (EPR) in the Eastern Tropical Pacific over an annual cycle (January-December 2011). Gravid females were collected twice monthly and incubated for 12 h without food to estimate EPR, weight-specific fecundity (Gf), spawning success (SS, percentage of females to spawn out of the total species incubated per month and season) and egg hatching success (EHS). This study reports the average EPR of 10 species and the monthly EPR and Gf of four planktonic calanoid copepods (Centropages furcatus, Temora discaudata, Pontellina sobrina, and Nannocalanus minor) that spawned with enough frequency to infer their seasonal reproductive patterns. These species showed distinct seasonal reproductive strategies. Most copepod species spawned sporadically with large EPR variability, while three copepod species reproduced throughout the year (C. furcatus, T. discaudata and P. sobrina) and N. minor spawned only during the mixed period (Feb-May). The four species had relatively similar average EPR (C. furcatus 16, T. discaudata 18, P. sobrina 13, and N. minor 12 eggs fem-1 day-1). These are the first EPR estimations of P. sobrina and its previously known reproductive period is expanded. A Canonical Correspondence Analysis (CCA) was used to analyze EPR and species abundance of all calanoid copepods (40 spp.) collected throughout the time series in relation to temperature, salinity, mixed layer depth (MLD), dissolved oxygen, and chlorophyll a (Chl-a) concentrations to identify the variables that best explained the copepod abundance variability. Temperature, Chl-a, and salinity had the strongest effect on the biological variables, linked to seasonal and episodic upwelling-downwelling processes in the surveyed area. As a result of moderate upwelling events and seasonal variation of environmental conditions, it appears relatively few species are capable of maintaining continuous reproduction under the relatively higher

iDNA at Sea: Recovery of Whale Shark (Rhincodon typus Mitochondrial DNA Sequences from the Whale Shark Copepod (Pandarus rhincodonicus Confirms Global Population Structure

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Mark Meekan

2017-12-01

Full Text Available The whale shark (Rhincodon typus is an iconic and endangered species with a broad distribution spanning warm-temperate and tropical oceans. Effective conservation management of the species requires an understanding of the degree of genetic connectivity among populations, which is hampered by the need for sampling that involves invasive techniques. Here, the feasibility of minimally-invasive sampling was explored by isolating and sequencing whale shark DNA from a commensal or possibly parasitic copepod, Pandarus rhincodonicus that occurs on the skin of the host. We successfully recovered mitochondrial control region DNA sequences (~1,000 bp of the host via DNA extraction and polymerase chain reaction from whole copepod specimens. DNA sequences obtained from multiple copepods collected from the same shark exhibited 100% sequence similarity, suggesting a persistent association of copepods with individual hosts. Newly-generated mitochondrial haplotypes of whale shark hosts derived from the copepods were included in an analysis of the genetic structure of the global population of whale sharks (644 sequences; 136 haplotypes. Our results supported those of previous studies and suggested limited genetic structuring across most of the species range, but the presence of a genetically unique and potentially isolated population in the Atlantic Ocean. Furthermore, we recovered the mitogenome and nuclear ribosomal genes of a whale shark using a shotgun sequencing approach on copepod tissue. The recovered mitogenome is the third mitogenome reported for the species and the first from the Mozambique population. Our invertebrate DNA (iDNA approach could be used to better understand the population structure of whale sharks, particularly in the Atlantic Ocean, and also for genetic analyses of other elasmobranchs parasitized by pandarid copepods.

Molecular evidence of the toxic effects of diatom diets on gene expression patterns in copepods.

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Chiara Lauritano

Full Text Available Diatoms are dominant photosynthetic organisms in the world's oceans and are considered essential in the transfer of energy through marine food chains. However, these unicellular plants at times produce secondary metabolites such as polyunsaturated aldehydes and other products deriving from the oxidation of fatty acids that are collectively termed oxylipins. These cytotoxic compounds are responsible for growth inhibition and teratogenic activity, potentially sabotaging future generations of grazers by inducing poor recruitment in marine organisms such as crustacean copepods.Here we show that two days of feeding on a strong oxylipin-producing diatom (Skeletonema marinoi is sufficient to inhibit a series of genes involved in aldehyde detoxification, apoptosis, cytoskeleton structure and stress response in the copepod Calanus helgolandicus. Of the 18 transcripts analyzed by RT-qPCR at least 50% were strongly down-regulated (aldehyde dehydrogenase 9, 8 and 6, cellular apoptosis susceptibility and inhibitor of apoptosis IAP proteins, heat shock protein 40, alpha- and beta-tubulins compared to animals fed on a weak oxylipin-producing diet (Chaetoceros socialis which showed no changes in gene expression profiles.Our results provide molecular evidence of the toxic effects of strong oxylipin-producing diatoms on grazers, showing that primary defense systems that should be activated to protect copepods against toxic algae can be inhibited. On the other hand other classical detoxification genes (glutathione S-transferase, superoxide dismutase, catalase, cytochrome P450 were not affected possibly due to short exposure times. Given the importance of diatom blooms in nutrient-rich aquatic environments these results offer a plausible explanation for the inefficient use of a potentially valuable food resource, the spring diatom bloom, by some copepod species.

Effects of cold selective breeding on the body length, fatty acid content, and productivity of the tropical copepod Apocyclops royi (Cyclopoida, Copepoda)

DEFF Research Database (Denmark)

Pan, Yen-Ju; Souissi, Anissa; Sadovskaya, Irina

2017-01-01

In this study, we conducted a novel approach of selective breeding by using temperature acclimation to enhance the aquaculture potential of the tropical cyclopoid copepod Apocyclops royi. Two copepod culture strains were acclimated separately at high (28°C, control strain) and low (18°C, selective...

Cyclopoid and calanoid copepod biodiversity in Indonesia

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Victor R. Alekseev

2013-10-01

Full Text Available Recent limnological investigations conducted on the large lakes of Indonesia provide valuable physical and ecological data for future environmental and developmental programmes, yet few studies have focused on zooplankton taxonomy. Here we describe Eucyclops troposperatus Alekseev et Yusoff n. sp. from a pond in Sumatra, and Mesocyclops jakartensis Alekseev n. sp. from a city pond in Jakarta, Java. In the pelagic zone of the lakes of Sulawesi we found only few copepod species. For the endemic cyclopoid Tropocyclops matanoensis Defaye, 2007, we propose a new subgenus, Defayeicyclops n. subg., and provide more data on the morphology as well as scanning electron microscopy and confocal laser scanning images of Tropocyclops (Defayeicyclops matanoensis. Two other cyclopoid species were possibly introduced to Sulawesi: Mesocyclops aequatorialis similis Van de Velde, 1984 from Africa and Thermocyclops crassus (Fischer, 1853 from Eurasia. A new subspecies, Phyllodiaptomus praedictus sulawesensis Alekseev et Vaillant n. ssp. (Calanoida, Diaptomidae, is described from the plankton of lake Tondano, North Sulawesi, Indonesia. The new subspecies resembles P. blanci (de Guerne et Richard, 1896 and P. wellekensae Dumont et Reddy, 1992. Phyllodiaptomus praedictus sulawesensis appears to be endemic to Sulawesi island. The form matanensis formerly treated as a subspecies of Eodiaptomus wolterecki Brehm, 1933 is here elevated to species rank, E. matanensis Brehm, 1933. A preliminary list of the copepod species found in Sulawesi and other large islands of Indonesia now includes more than 60 species. An updated key to the Southeast Asian species of the genus Eucyclops is provided.

Lethal and sublethal effects of naphthalene and 1,2-dimethylnaphthalene on naupliar and adult stages of the marine cyclopoid copepod Oithona davisae

International Nuclear Information System (INIS)

Saiz, Enric; Movilla, Juancho; Yebra, Lidia; Barata, Carlos; Calbet, Albert

2009-01-01

Short-term (24 h) exposure experiments have been conducted to determine the effects of two environmental relevant polycyclic aromatic hydrocarbons (PAHs), naphthalene (NAPH) and dimethylnaphthalene (C2-NAPH), on the naupliar and adult stages of the marine cyclopoid copepod Oithona davisae. To resemble more realistic conditions, those exposure experiments were conducted under the presence of food. The naupliar stages evidenced lower tolerance to PAH exposure regarding narcotic and lethal effects than adults. Copepod feeding activity showed to be very sensitive to the presence of the studied PAHs, detrimental effects occurring at toxic concentrations ca. 2-3 fold lower than for narcotic effects. In addition we report PAH-mediated changes in cell size and growth rate of the prey item, the heterotrophic dinoflagellate Oxyrrhis marina, that could indirectly affect copepod feeding and help explain hormesis-like responses in our feeding experiments. - The feeding activity of copepods is very sensitive to the direct and indirect (prey-viability mediated) effects of polycyclic aromatic hydrocarbons

Lethal and sublethal effects of naphthalene and 1,2-dimethylnaphthalene on naupliar and adult stages of the marine cyclopoid copepod Oithona davisae

Energy Technology Data Exchange (ETDEWEB)

Saiz, Enric [Institut de Ciencies del Mar (ICM), CSIC, Ps. Maritim de la Barceloneta 37-49, E-08003 Barcelona, Catalunya (Spain)], E-mail: enric@icm.csic.es; Movilla, Juancho; Yebra, Lidia [Institut de Ciencies del Mar (ICM), CSIC, Ps. Maritim de la Barceloneta 37-49, E-08003 Barcelona, Catalunya (Spain); Barata, Carlos [Departament de Quimica Ambiental, Institut de Diagnostic Ambiental i Estudis de l' Aigua (IDAEA), CSIC, C/Jordi Girona 18-26, E-08034 Barcelona, Catalunya (Spain); Calbet, Albert [Institut de Ciencies del Mar (ICM), CSIC, Ps. Maritim de la Barceloneta 37-49, E-08003 Barcelona, Catalunya (Spain)

2009-04-15

Short-term (24 h) exposure experiments have been conducted to determine the effects of two environmental relevant polycyclic aromatic hydrocarbons (PAHs), naphthalene (NAPH) and dimethylnaphthalene (C2-NAPH), on the naupliar and adult stages of the marine cyclopoid copepod Oithona davisae. To resemble more realistic conditions, those exposure experiments were conducted under the presence of food. The naupliar stages evidenced lower tolerance to PAH exposure regarding narcotic and lethal effects than adults. Copepod feeding activity showed to be very sensitive to the presence of the studied PAHs, detrimental effects occurring at toxic concentrations ca. 2-3 fold lower than for narcotic effects. In addition we report PAH-mediated changes in cell size and growth rate of the prey item, the heterotrophic dinoflagellate Oxyrrhis marina, that could indirectly affect copepod feeding and help explain hormesis-like responses in our feeding experiments. - The feeding activity of copepods is very sensitive to the direct and indirect (prey-viability mediated) effects of polycyclic aromatic hydrocarbons.

Differential dormancy of co-occurring copepods

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Ohman, Mark D.; Drits, Aleksandr V.; Elizabeth Clarke, M.; Plourde, Stéphane

1998-08-01

Four species of planktonic calanoid copepods that co-occur in the California Current System ( Eucalanus californicus Johnson, Rhincalanus nasutus Giesbrecht, Calanus pacificus californicus Brodsky, and Metridia pacifica Brodsky) were investigated for evidence of seasonal dormancy in the San Diego Trough. Indices used to differentiate actively growing from dormant animals included developmental stage structure and vertical distribution; activity of aerobic metabolic enzymes (Citrate Synthase and the Electron Transfer System complex); investment in depot lipids (wax esters and triacylglycerols); in situ grazing activity from gut fluorescence; and egg production rates in simulated in situ conditions. None of the 4 species exhibited a canonical calanoid pattern of winter dormancy - i.e., synchronous developmental arrest as copepodid stage V, descent into deep waters, reduced metabolism, and lack of winter reproduction. Instead, Calanus pacificus californicus has a biphasic life history in this region, with an actively reproducing segment of the population in surface waters overlying a deep dormant segment in winter. Eucalanus californicus is dormant as both adult females and copepodid V's, although winter females respond relatively rapidly to elevated food and temperature conditions; they begin feeding and producing eggs within 2-3 days. Rhincalanus nasutus appears to enter dormancy as adult females, although the evidence is equivocal. Metridia pacifica shows no evidence of dormancy, with sustained active feeding, diel vertical migration behavior, and elevated activity of metabolic enzymes in December as well as in June. The four species also differ markedly in water content, classes of storage lipids, and specific activity of Citrate Synthase. These results suggest that copepod dormancy traits and structural composition reflect diverse adaptations to regional environmental conditions rather than a uniform, canonical series of traits that remain invariant among taxa

Composition and physical state of phospholipids in calanoid copepods from India and Norway

Digital Repository Service at National Institute of Oceanography (India)

Farkas, T.; Storebakken, T.; Bhosle, N.B.

The fatty acid composition and physical state of isolated phospholipids obtained from marine copepods collected on the Southwest coast of India (Calanus spp.) and the west coast of Norway (Calanus finmarchicus) were investigated to compare...

Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

Science.gov (United States)

Kiko, R.; Hauss, H.; Buchholz, F.; Melzner, F.

2015-10-01

Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2 and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply considerably fuels bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a downregulation of ammonium excretion. Here we show that exposure to OMZ conditions can result in strong depression of respiration and ammonium excretion in calanoid copepods and euphausiids from the Eastern Tropical North Atlantic and the Eastern Tropical South Pacific. These physiological responses need to be taken into account when estimating DVM-mediated fluxes of carbon and nitrogen into OMZs.

Species-specific vulnerability of Arctic copepods to oil contamination and global warming

DEFF Research Database (Denmark)

Dinh, Khuong Van; Nielsen, Torkel Gissel

Arctic ecosystems are predicted to have more severe effects from global warming as during the last decades the temperatures have increased in this region at a rate of 2-4 times higher than the global average. In addition, oil exploitation and shipping activities in the Arctic are predicted...... to increase under global warming as the result of the retreat of sea ice, posing the risk of oil contamination. It is poorly known how cold adapted copepods in the Arctic deal with the combined effects of global warming and oil exposure. To address this, we exposed females of two copepods species Calanus...... of temperatures. Notably, exposure to high pyrene resulted in ca. 70% of mortality in C. finmarchicus, the species with North Atlantic Origin, that was two times higher than the mortality observed for C. glacialis, the true Arctic species. These results suggest that extreme temperature under global warming...

Molecular Phylogeny and Revision of Copepod Orders (Crustacea: Copepoda).

Science.gov (United States)

Khodami, Sahar; McArthur, J Vaun; Blanco-Bercial, Leocadio; Martinez Arbizu, Pedro

2017-08-22

For the first time, the phylogenetic relationships between representatives of all 10 copepod orders have been investigated using 28S and 18S rRNA, Histone H3 protein and COI mtDNA. The monophyly of Copepoda (including Platycopioida Fosshagen, 1985) is demonstrated for the first time using molecular data. Maxillopoda is rejected, as it is a polyphyletic group. The monophyly of the major subgroups of Copepoda, including Progymnoplea Lang, 1948 (=Platycopioida); Neocopepoda Huys and Boxshall, 1991; Gymnoplea Giesbrecht, 1892 (=Calanoida Sars, 1903); and Podoplea Giesbrecht, 1892, are supported in this study. Seven copepod orders are monophyletic, including Platycopioida, Calanoida, Misophrioida Gurney, 1933; Monstrilloida Sars, 1901; Siphonostomatoida Burmeister, 1834; Gelyelloida Huys, 1988; and Mormonilloida Boxshall, 1979. Misophrioida (=Propodoplea Lang, 1948) is the most basal Podoplean order. The order Cyclopoida Burmeister, 1835, is paraphyletic and now encompasses Poecilostomatoida Thorell, 1859, as a sister to the family Schminkepinellidae Martinez Arbizu, 2006. Within Harpacticoida Sars, 1903, both sections, Polyarthra Lang, 1948, and Oligoarthra Lang, 1948, are monophyletic, but not sister groups. The order Canuelloida is proposed while maintaining the order Harpacticoida s. str. (Oligoarthra). Cyclopoida, Harpacticoida and Cyclopinidae are redefined, while Canuelloida ordo. nov., Smirnovipinidae fam. nov. and Cyclopicinidae fam. nov are proposed as new taxa.

First report on the contribution of small-sized species to the copepod community structure of the southern Patagonian shelf (Argentina, 47-55°S

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Julieta Carolina Antacli

2014-03-01

Full Text Available The copepod community structure, with special emphasis on small-sized species, was studied over the southern Patagonian shelf in late summer 2004, applying the first plankton sampling in the region with a fine-mesh (66 μm net. The key role of the copepods Drepanopus forcipatus and Calanus australis was confirmed, but also the high abundance and frequency of occurrence of the microcopepods Oithona helgolandica and Microsetella norvegica and of the medium-sized copepod Ctenocalanus vanus were revealed. Copepod community structure was nearly homogenous over the entire study area. Drepanopus forcipatus, O. helgolandica and M. norvegica were identified as the typical species of the region, although secondarily C. australis and Oithona atlantica also contributed significantly to community similarity across the area. The study of interspecific relationships of dominant copepods indicated that D. forcipatus and C. australis were associated positively with O. helgolandica, while C. vanus, and M. norvegica constituted a separate assemblage with Clausocalanus brevipes and O. atlantica. The importance of fine-mesh-size nets for collecting the smaller size fractions of mesozooplankton and for accurately portraying the mesozooplankton assemblage structure in the area is stressed by this study.

Short-term exposure to gold nanoparticle suspension impairs swimming behavior in a widespread calanoid copepod.

Science.gov (United States)

Michalec, François-Gaël; Holzner, Markus; Barras, Alexandre; Lacoste, Anne-Sophie; Brunet, Loïc; Lee, Jae-Seong; Slomianny, Christian; Boukherroub, Rabah; Souissi, Sami

2017-09-01

Calanoid copepods play an important role in the functioning of marine and brackish ecosystems. Information is scarce on the behavioral toxicity of engineered nanoparticles to these abundant planktonic organisms. We assessed the effects of short-term exposure to nonfunctionalized gold nanoparticles on the swimming behavior of the widespread estuarine copepod Eurytemora affinis. By means of three-dimensional particle tracking velocimetry, we reconstructed the trajectories of males, ovigerous and non-ovigerous females. We quantified changes in their swimming activity and in the kinematics and geometrical properties of their motion, three important descriptors of the motility patterns of zooplankters. In females, exposure to gold nanoparticles in suspension (11.4 μg L -1 ) for 30 min caused depressed activity and lower velocity and acceleration, whereas the same exposure caused minimal effects in males. This response differs clearly from the hyperactive behavior that is commonly observed in zooplankters exposed to pollutants, and from the generally lower sensitivity of female copepods to toxicants. Accumulation of gold nanoparticles on the external appendages was not observed, precluding mechanical effects. Only very few nanoparticles appeared sporadically in the inner part of the gut in some samples, either as aggregates or as isolated nanoparticles, which does not suggest systemic toxicity resulting from pronounced ingestion. Hence, the precise mechanisms underlying the behavioral toxicity observed here remain to be elucidated. These results demonstrate that gold nanoparticles can induce marked behavioral alterations at very low concentration and short exposure duration. They illustrate the applicability of swimming behavior as a suitable and sensitive endpoint for investigating the toxicity of nanomaterials present in estuarine and marine environments. Changes in swimming behavior may impair the ability of planktonic copepods to interact with their environment

Identification and molecular characterization of nitric oxide synthase (NOS) gene in the intertidal copepod Tigriopus japonicus.

Science.gov (United States)

Jeong, Chang-Bum; Kang, Hye-Min; Seo, Jung Soo; Park, Heum Gi; Rhee, Jae-Sung; Lee, Jae-Seong

2016-02-10

In copepods, no information has been reported on the structure or molecular characterization of the nitric oxide synthase (NOS) gene. In the intertidal copepod Tigriopus japonicus, we identified a NOS gene that is involved in immune responses of vertebrates and invertebrates. In silico analyses revealed that nitric oxide (NO) synthase domains, such as the oxygenase and reductase domains, are highly conserved in the T. japonicus NOS gene. The T. japonicus NOS gene was highly transcribed in the nauplii stages, implying that it plays a role in protecting the host during the early developmental stages. To examine the involvement of the T. japonicus NOS gene in the innate immune response, the copepods were exposed to lipopolysaccharide (LPS) and two Vibrio sp. After exposure to different concentrations of LPS and Vibrio sp., T. japonicus NOS transcription was significantly increased over time in a dose-dependent manner, and the NO/nitrite concentration increased as well. Taken together, our findings suggest that T. japonicus NOS transcription is induced in response to an immune challenge as part of the conserved innate immunity. Copyright © 2015 Elsevier B.V. All rights reserved.

Coexistence and succession of copepod species in the Mandovi and Zuari estuaries, Goa

Digital Repository Service at National Institute of Oceanography (India)

Goswami, S.C.

Observations were made on the copepod species association and succession at six stations in the Mandovi-Zuari estuarine system of Goa, India. A total of 55 species belonging to 25 genera and 18 families were encountered in the surface collections...

Community structure of copepods in the oceanic and neritic waters off Adélie and George V Land, East Antarctica, during the austral summer of 2008

Science.gov (United States)

Tachibana, Aiko; Watanabe, Yuko; Moteki, Masato; Hosie, Graham W.; Ishimaru, Takashi

2017-06-01

Copepods are one of the most important components of the Southern Ocean food web, and are widely distributed from surface to deeper waters. We conducted discrete depth sampling to clarify the community structure of copepods from the epi- to bathypelagic layers of the oceanic and neritic waters off Adélie and George V Land, East Antarctica, in the austral summer of 2008. Notably high diversity and species numbers were observed in the meso- and bathypelagic layers. Cluster analysis based on the similarity of copepod communities identified seven cluster groups, which corresponded well with water masses. In the epi- and upper- mesopelagic layers of the oceanic zone, the SB (Southern Boundary of the Antarctic Circumpolar Current) divided copepod communities. Conversely, in the lower meso- and bathypelagic layers (500-2000 m depth), communities were consistent across the SB. In these layers, the distributions of copepod species were separated by habitat depth ranges and feeding behaviour. The different food webs occur in the epipelagic layer with habitat segregation by zooplankton in their horizontal distribution ranges.

Corallovexiidae, a new family of transformed copepods endoparasitic in reef corals with two new genera and ten new species from Curaçao

NARCIS (Netherlands)

Stock, Jan H.

1975-01-01

Quite a few endoparasitic copepods are known from Indo-Pacific stony corals, but not a single species has so far been recorded from the West Indies. Intensive search in the past few decades has even supported the prevailing opinion that West Indian stony corals are devoid of endoparasitic copepods,

Toxicity tests with crustaceans for detecting sublethal effects of potential endocrine disrupting chemicals

DEFF Research Database (Denmark)

Wollenberger, Leah

/antagonistic activity with the ecdysteroid-responsive Drosophila melanogaster BII cell line 6) to draft an OECD guideline proposal for testing of chemicals based on the experimental work performed within this study In preliminary investigations with A. tonsa were studied various parameters related to processes......New and updated test methods to detect and characterise endocrine disrupting chemicals are urgently needed for the purpose of environmental risk assessment. Although endocrine disruption in invertebrates has not been studied as extensive as in vertebrates, in particular in fish, numerous reports...... of the present Ph.D. project were: 1) to develop a fully synthetic saltwater medium suitable for laboratory culturing of marine copepods including their feeding organism as well as for toxicity testing 2) to identify sensitive endpoints related to growth, development and reproduction of the pelagic calanoid...

Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice

Science.gov (United States)

Lewis, Ceri N.; Brown, Kristina A.; Edwards, Laura A.; Cooper, Glenn; Findlay, Helen S.

2013-01-01

The Arctic Ocean already experiences areas of low pH and high CO2, and it is expected to be most rapidly affected by future ocean acidification (OA). Copepods comprise the dominant Arctic zooplankton; hence, their responses to OA have important implications for Arctic ecosystems, yet there is little data on their current under-ice winter ecology on which to base future monitoring or make predictions about climate-induced change. Here, we report results from Arctic under-ice investigations of copepod natural distributions associated with late-winter carbonate chemistry environmental data and their response to manipulated pCO2 conditions (OA exposures). Our data reveal that species and life stage sensitivities to manipulated OA conditions were correlated with their vertical migration behavior and with their natural exposures to different pCO2 ranges. Vertically migrating adult Calanus spp. crossed a pCO2 range of >140 μatm daily and showed only minor responses to manipulated high CO2. Oithona similis, which remained in the surface waters and experienced a pCO2 range of <75 μatm, showed significantly reduced adult and nauplii survival in high CO2 experiments. These results support the relatively untested hypothesis that the natural range of pCO2 experienced by an organism determines its sensitivity to future OA and highlight that the globally important copepod species, Oithona spp., may be more sensitive to future high pCO2 conditions compared with the more widely studied larger copepods. PMID:24297880

Lipid sac area as a proxy for individual lipid content of arctic calanoid copepods

OpenAIRE

Vogedes, Daniel; Varpe, ?ystein; S?reide, Janne E.; Graeve, Martin; Berge, J?rgen; Falk-Petersen, Stig

2010-01-01

We present an accurate, fast, simple and non-destructive photographic method to estimate wax ester and lipid content in single individuals of the calanoid copepod genus Calanus and test this method against gas-chromatographic lipid measurements.

Abundance, distribution and population structure of the copepod Calanus finmarchicus in a springtime right whale feeding area in the southwestern Gulf of Maine

Science.gov (United States)

Wishner, Karen F.; Schoenherr, Jill R.; Beardsley, Robert; Chen, Changsheng

Springtime aggregations of the planktivorous right whale ( Eubalaena glacialis) occur in the northern Great South Channel region of the southwestern Gulf of Maine, where they feed upon dense concentrations of the copepod Calanus finmarchicus. This association was studied during the multidisciplinary South Channel Ocean Productivity Experiment (SCOPEX) in 1988 and 1989. The spatial and temporal variability of the abundance, geographic distribution, and population structure of these copepods were analyzed using data from 99 vertically-stratified or horizontally-sequenced MOCNESS plankton tows. Higher water column abundances and higher relative proportion of older copepod lifestages occurred near feeding whales compared to sites without whales, but total water column copepod biomass and Calanus abundance did not always differ between these types of locations. This suggests that the whales seek out aggregations of older copepod lifestages rather than simply the most dense aggregations. Other factors (and perhaps an element of chance) may influence which specific patches, among all patches potentially suitable in terms of copepod abundance and age composition, the whales utilize at a particular time. The times and locations of the highest Calansus water column abundances varied between years, as did the presence of feeding whales, probably because of year-to-year differences in the springtime temperature cycle and current strength. A temporal progression of lifestages occurred within the region in both years during the roughly 3-week duration of each survey, indicative of a growing rather than a diapausing population, at least up to the copepodite 4 (C4) stage. Due in part to a delay in the springtime warming in 1989 compared to 1988, the copepod development cycle, which is largely driven by in situ temperature, was delayed about 1-2 weeks in 1989. Peak abundances of younger Calanus were found in the northwestern part of the region each year, whereas peak abundances of

Detailed surface morphology of the 'lobster louse' copepod, Nicothoë astaci, a haematophagous gill parasite of the European lobster, Homarus gammarus.

Science.gov (United States)

Davies, Charlotte E; Thomas, Gethin R; Maffeis, Thierry G G; Wootton, Emma C; Penny, Mark W; Rowley, Andrew F

2014-10-01

The ectoparasitic copepod, Nicothoë astaci (the 'lobster louse'), infests the gills of the European lobster, Homarus gammarus. There have been limited studies on this haematophagous species; therefore knowledge of this parasite is rudimentary. The current study examines the surface morphology of this parasitic copepod, detached from the host, concentrating on adaptations of the suctorial mouthpart, the oral disc. Cryo-scanning electron microscopy revealed structural adaptations that facilitate attachment of these parasites to the gill filaments of their lobster host. The aperture of the feeding channel, through which host haemolymph is drawn, is only ca. 5μm in diameter. The edge of the oral disc is lined with numerous setae, whilst the surface of the disc is covered with large numbers of small (copepod host. Copyright © 2014 Elsevier Inc. All rights reserved.

Spliced leader-based analyses reveal the effects of polycyclic aromatic hydrocarbons on gene expression in the copepod Pseudodiaptomus poplesia.

Science.gov (United States)

Zhuang, Yunyun; Yang, Feifei; Xu, Donghui; Chen, Hongju; Zhang, Huan; Liu, Guangxing

2017-02-01

Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic and carcinogenic pollutants that can adversely affect the development, growth and reproduction of marine organisms including copepods. However, knowledge on the molecular mechanisms regulating the response to PAH exposure in marine planktonic copepods is limited. In this study, we investigated the survival and gene expression of the calanoid copepod Pseudodiaptomus poplesia upon exposure to two PAHs, 1, 2-dimethylnaphthalene (1, 2-NAPH) and pyrene. Acute toxicity responses resulted in 96-h LC 50 of 788.98μgL -1 and 54.68μgL -1 for 1, 2-NAPH and pyrene, respectively. Using the recently discovered copepod spliced leader as a primer, we constructed full-length cDNA libraries from copepods exposed to sublethal concentrations and revealed 289 unique genes of diverse functions, including stress response genes and novel genes previously undocumented for this species. Eighty-three gene families were specifically expressed in PAH exposure libraries. We further analyzed the expression of seven target genes by reverse transcription-quantitative PCR in a time-course test with three sublethal concentrations. These target genes have primary roles in detoxification, oxidative defense, and signal transduction, and include different forms of glutathione S-transferase (GST), glutathione peroxidases (GPX), peroxiredoxin (PRDX), methylmalonate-semialdehyde dehydrogenase (MSDH) and ras-related C3 botulinum toxin substrate (RAC1). Expression stability of seven candidate reference genes were evaluated and the two most stable ones (RPL15 and RPS20 for 1, 2-NAPH exposure, RPL15 and EF1D for pyrene exposure) were used to normalize the expression levels of the target genes. Significant upregulation was detected in GST-T, GST-DE, GPX4, PRDX6 and RAC1 upon 1, 2-NAPH exposure, and GST-DE and MSDH upon pyrene exposure. These results indicated that the oxidative stress was induced and that signal transduction might be affected by PAH

Age- and size-dependent mating performance and fertility in a pelagic copepod, Temora longicornis

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Kiørboe, Thomas

2011-01-01

Prepress abstract: In many species, size and age have been shown to be strong determinants of the reproductive success for both sexes. Here we examine age- and size dependent reproductive performance (egg- and sperm production, mating success) in a pelagic copepod. Compared to smaller males, larger...... males produce larger spermatophores containing more spermatozoa, and fertilize a larger fraction of available females. Females mating with large males produce more offspring than those mating with small males. Similarly, large females have higher egg production rates as well as a higher life-time egg...... fertilize females for only about eight days after they mature. The strong size- and age-dependent fertility observed in this species is conducive to the development of sexual selection via mate choice for young and large partners, as has been shown in one other copepod species...

Transcriptome sequencing and de novo analysis of the copepod Calanus sinicus using 454 GS FLX.

Directory of Open Access Journals (Sweden)

Juan Ning

Full Text Available BACKGROUND: Despite their species abundance and primary economic importance, genomic information about copepods is still limited. In particular, genomic resources are lacking for the copepod Calanus sinicus, which is a dominant species in the coastal waters of East Asia. In this study, we performed de novo transcriptome sequencing to produce a large number of expressed sequence tags for the copepod C. sinicus. RESULTS: Copepodid larvae and adults were used as the basic material for transcriptome sequencing. Using 454 pyrosequencing, a total of 1,470,799 reads were obtained, which were assembled into 56,809 high quality expressed sequence tags. Based on their sequence similarity to known proteins, about 14,000 different genes were identified, including members of all major conserved signaling pathways. Transcripts that were putatively involved with growth, lipid metabolism, molting, and diapause were also identified among these genes. Differentially expressed genes related to several processes were found in C. sinicus copepodid larvae and adults. We detected 284,154 single nucleotide polymorphisms (SNPs that provide a resource for gene function studies. CONCLUSION: Our data provide the most comprehensive transcriptome resource available for C. sinicus. This resource allowed us to identify genes associated with primary physiological processes and SNPs in coding regions, which facilitated the quantitative analysis of differential gene expression. These data should provide foundation for future genetic and genomic studies of this and related species.

Active avoidance from a crude oil soluble fraction by an Andean paramo copepod.

Science.gov (United States)

Araújo, Cristiano V M; Moreira-Santos, Matilde; Sousa, José P; Ochoa-Herrera, Valeria; Encalada, Andrea C; Ribeiro, Rui

2014-09-01

Several oil spills due to ruptures in the pipeline oil systems have occurred at the Andean paramo. A sample of this crude oil was mixed with water from a nearby Andean lagoon and the toxicity of the soluble fraction was assessed through lethal and avoidance assays with a locally occurring copepod (Boeckella occidentalis intermedia). The integration of mortality and avoidance aimed at predicting the immediate decline of copepod populations facing an oil leakage. The 24-h median lethal PAH concentration was 42.7 (26.4-91.6) µg L(-1). In the 12-h avoidance assay, 30% avoidance was recorded at the highest PAH concentration (19.4 µg L(-1)). The mortality at this PAH concentration would be of 25% and, thus, the population immediate decline would be of 55%. The inclusion of non-forced exposure testing with the quantification of the avoidance response in environmental risk assessments is, therefore, supported due to underestimation of the lethal assays.

Effects of the oxylipin-producing diatom Skeletonema marinoi on gene expression levels of the calanoid copepod Calanus sinicus.

Science.gov (United States)

Lauritano, Chiara; Carotenuto, Ylenia; Vitiello, Valentina; Buttino, Isabella; Romano, Giovanna; Hwang, Jiang-Shiou; Ianora, Adrianna

2015-12-01

Diatoms are eukaryotic unicellular plants that constitute one of the major components of marine phytoplankton, comprising up to 40% of annual productivity at sea and representing 25% of global carbon-fixation. Diatoms have traditionally been considered a preferential food for zooplankton grazers such as copepods, but, in the last two decades, this beneficial role has been challenged after the discovery that many species of diatoms produce toxic metabolites, collectively termed oxylipins, that induce reproductive failure in zooplankton grazers. Diatoms are the dominant natural diet of Calanus sinicus, a cold-temperate calanoid copepod that supports secondary production of important fisheries in the shelf ecosystems of the Northwest Pacific Ocean, Yellow Sea, Sea of Japan and South China Sea. In this study, the effect of the oxylipin-producing diatom Skeletonema marinoi on C. sinicus has been evaluated by analyzing expression level changes of genes involved in defense and detoxification systems. Results show that C. sinicus is more resistant to a diet of this diatom species in terms of gene expression patterns, compared to the congeneric species Calanus helgolandicus which is an important constituent of the temperate waters of the Atlantic Ocean and northern Mediterranean Sea. These findings contribute to the better understanding of genetic and/or phenotypic flexibility of copepod species and their capabilities to cope with stress by identifying molecular markers (such as stress and detoxification genes) as biosensors for environmental perturbations (e.g. toxins and contaminants) affecting marine copepods. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Food-web inferences of stable isotope spatial patterns in copepods and yellowfin tuna in the pelagic eastern Pacific Ocean

Science.gov (United States)

Olson, Robert J.; Popp, Brian N.; Graham, Brittany S.; López-Ibarra, Gladis A.; Galván-Magaña, Felipe; Lennert-Cody, Cleridy E.; Bocanegra-Castillo, Noemi; Wallsgrove, Natalie J.; Gier, Elizabeth; Alatorre-Ramírez, Vanessa; Ballance, Lisa T.; Fry, Brian

2010-07-01

Evaluating the impacts of climate and fishing on oceanic ecosystems requires an improved understanding of the trophodynamics of pelagic food webs. Our approach was to examine broad-scale spatial relationships among the stable N isotope values of copepods and yellowfin tuna ( Thunnus albacares), and to quantify yellowfin tuna trophic status in the food web based on stable-isotope and stomach-contents analyses. Using a generalized additive model fitted to abundance-weighted-average δ 15N values of several omnivorous copepod species, we examined isotopic spatial relationships among yellowfin tuna and copepods. We found a broad-scale, uniform gradient in δ 15N values of copepods increasing from south to north in a region encompassing the eastern Pacific warm pool and parts of several current systems. Over the same region, a similar trend was observed for the δ 15N values in the white muscle of yellowfin tuna caught by the purse-seine fishery, implying limited movement behavior. Assuming the omnivorous copepods represent a proxy for the δ 15N values at the base of the food web, the isotopic difference between these two taxa, “ ΔYFT-COP,” was interpreted as a trophic-position offset. Yellowfin tuna trophic-position estimates based on their bulk δ 15N values were not significantly different than independent estimates based on stomach contents, but are sensitive to errors in the trophic enrichment factor and the trophic position of copepods. An apparent inshore-offshore, east to west gradient in yellowfin tuna trophic position was corroborated using compound-specific isotope analysis of amino acids conducted on a subset of samples. The gradient was not explained by the distribution of yellowfin tuna of different sizes, by seasonal variability at the base of the food web, or by known ambit distances (i.e. movements). Yellowfin tuna stomach contents did not show a regular inshore-offshore gradient in trophic position during 2003-2005, but the trophic

The chronic toxicity of molybdate to marine organisms. I. Generating reliable effects data

Energy Technology Data Exchange (ETDEWEB)

Heijerick, D.G., E-mail: Dagobert.heijerick@arche-consulting.be [ARCHE - Assessing Risks of Chemicals, Stapelplein 70 Bus 104, Gent (Belgium); Regoli, L. [International Molybdenum Association, 4 Heathfield Terrace, London, W4 4JE (United Kingdom); Stubblefield, W. [Oregon State University, Department of Environmental and Molecular Toxicology, 421 Weniger Hall, Corvallis, OR 97331 (United States)

2012-07-15

A scientific research program was initiated by the International Molybdenum Association (IMOA) which addressed identified gaps in the environmental toxicity data for the molybdate ion (MoO{sub 4}{sup 2-}). These gaps were previously identified during the preparation of EU-REACH-dossiers for different molybdenum compounds (European Union regulation on Registration, Evaluation, Authorization and Restriction of Chemical substances; EC, 2006). Evaluation of the open literature identified few reliable marine ecotoxicological data that could be used for deriving a Predicted No-Effect Concentration (PNEC) for the marine environment. Rather than calculating a PNEC{sub marine} using the assessment factor methodology on a combined freshwater/marine dataset, IMOA decided to generate sufficient reliable marine chronic data to permit derivation of a PNEC by means of the more scientifically robust species sensitivity distribution (SSD) approach (also called the statistical extrapolation approach). Nine test species were chronically exposed to molybdate (added as sodium molybdate dihydrate, Na{sub 2}MoO{sub 4}{center_dot}2H{sub 2}O) according to published standard testing guidelines that are acceptable for a broad range of regulatory purposes. The selected test organisms were representative for typical marine trophic levels: micro-algae/diatom (Phaeodactylum tricornutum, Dunaliella tertiolecta), macro-alga (Ceramium tenuicorne), mysids (Americamysis bahia), copepod (Acartia tonsa), fish (Cyprinodon variegatus), echinoderms (Dendraster exentricus, Strongylocentrotus purpuratus) and molluscs (Mytilus edulis, Crassostrea gigas). Available NOEC/EC{sub 10} levels ranged between 4.4 mg Mo/L (blue mussel M. edulis) and 1174 mg Mo/L (oyster C. gigas). Using all available reliable marine chronic effects data that are currently available, a HC{sub 5,50%} (median hazardous concentration affecting 5% of the species) of 5.74 (mg Mo)/L was derived with the statistical extrapolation approach, a

Spatial patterns of copepod biodiversity in relation to a tidal front system in the main spawning and nursery area of the Argentine hake Merluccius hubbsi

Science.gov (United States)

Temperoni, B.; Viñas, M. D.; Martos, P.; Marrari, M.

2014-11-01

Copepods play an important role in marine ecosystems as a direct link of energy transfer between primary producers and higher trophic level consumers, such as fish. In the Argentine Sea, the Patagonian stock of Argentine hake Merluccius hubbsi spawns from late austral spring (December) to early autumn (April) in the northern Patagonian shelf region (43°-45°30‧S), in association with a highly productive tidal front system. Since hake larvae prey mainly upon copepods, the objective of this study was to assess the spatial variability in the abundance and diversity of these potential food items in different sectors of the front, as one of the possible factors affecting hake recruitment success. Two complementary mesh sizes (67 and 300 μm) were used to accurately target the entire copepod size spectrum. The copepod community was dominated by developmental stages sustain M. hubbsi larval growth resulting from high availability of adequate prey, the suitable thermal ranges, and the existence of retention mechanisms.

Escape from viscosity : the kinematics and hydrodynamics of copepod foraging and escape swimming

NARCIS (Netherlands)

van Duren, LA; Videler, JJ

Feeding and escape swimming in adult females of the calanoid copepod. Temora lopgicornis Muller were investigated and compared. Swimming velocities were calculated using a 3-D filming setup., Foraging velocities ranged between 2 and 6 min s(-1), while maximum velocities of up to 80 mm s(-1) were

Natural copepods are superior to enriched artemia nauplii as feed for halibut larvae (Hippoglossus hippoglossus) in terms of survival, pigmentation and retinal morphology: relation to dietary essential fatty acids.

Science.gov (United States)

Shields, R J; Bell, J G; Luizi, F S; Gara, B; Bromage, N R; Sargent, J R

1999-06-01

Replicate groups of halibut larvae were fed to d 71 post-first feeding (PFF) either the marine copepod, Eurytemora velox, or Artemia nauplii doubly enriched with the marine chromist or golden algae, Schizochytrium sp., (Algamac 2000) and a commercial oil emulsion (SuperSelco). The fatty acid compositions of eyes, brains and livers from larvae fed the two diets were measured, and indices of growth, eye migration and skin pigmentation were recorded along with histological examinations of eye and liver. The docosahexaenoic acid [22:6(n-3); DHA]/eicosapentaenoic acid [20:5(n-3); EPA] ratios in Artemia nauplii enriched with the SuperSelco and Algamac 2000 were 0.4 and 1.0, respectively. The E. velox copepods were divided into two size ranges (125-250 and 250-400 microm) with the smaller size range containing the highest level of (n-3) highly unsaturated fatty acids (HUFA). The DHA/EPA ratios for the two size ranges of copepods were 2.0 and 0.9, respectively. The total lipids of eyes, brains and livers of larvae fed copepods had higher levels of DHA and lower levels of EPA than those of larvae fed enriched Artemia. The percentage of survival of the halibut larvae was significantly higher when copepods rather than enriched Artemia nauplii were fed, but larval specific growth rates did not differ. The indices of eye migration were high and not significantly different in larvae fed the two diets, but the percentage of larvae undergoing successful metamorphosis (complete eye migration and dorsal pigmentation) was higher in larvae fed copepods (40%) than in larvae fed enriched Artemia (4%). The rod/cone ratios in histological sections of the retina were 2.5 +/- 0.7 in larvae fed copepods and 1.3 +/- 0.6 in larvae fed enriched Artemia (P < 0.01). Histological examination of the livers and intestines of the larvae were consistent with better assimilation of lipid from copepods than lipid from Artemia nauplii up to 46 d post-first feeding. Thus, marine copepods are superior to

Population dynamics and life history strategies of the dominant copepods in a sub-arctic Greenlandic fjord

DEFF Research Database (Denmark)

Kjellerup, Sanne; Nielsen, Torkel Gissel

Investigations of the Arctic and Sub-Arctic pelagic food web have previously focused on the copepod genus Calanus, as they often dominate the mesozooplankton community and serve as a lipid rich food source for higher trophic levels. However, if night samples are considered a different food web...... might emerges with the omnivorous copepod Metridia spp. in a major role. Biology of Metridia is practically unknown but deviates from Calanus e.g. Metridia does not hibernate but stays active yearlong benefiting from being omnivore. In the present study abundance, depth distribution, and egg and pellet...... hibernating Calanus. M. longa might thereby also have a central role in the lipid rich food chain which is a distinct feature for Arctic and Sub-Arctic ecosystems...

Billions of basepairs of recently expanded, repetitive sequences are eliminated from the somatic genome during copepod development.

Science.gov (United States)

Sun, Cheng; Wyngaard, Grace; Walton, D Brian; Wichman, Holly A; Mueller, Rachel Lockridge

2014-03-11

Chromatin diminution is the programmed deletion of DNA from presomatic cell or nuclear lineages during development, producing single organisms that contain two different nuclear genomes. Phylogenetically diverse taxa undergo chromatin diminution--some ciliates, nematodes, copepods, and vertebrates. In cyclopoid copepods, chromatin diminution occurs in taxa with massively expanded germline genomes; depending on species, germline genome sizes range from 15 - 75 Gb, 12-74 Gb of which are lost from pre-somatic cell lineages at germline--soma differentiation. This is more than an order of magnitude more sequence than is lost from other taxa. To date, the sequences excised from copepods have not been analyzed using large-scale genomic datasets, and the processes underlying germline genomic gigantism in this clade, as well as the functional significance of chromatin diminution, have remained unknown. Here, we used high-throughput genomic sequencing and qPCR to characterize the germline and somatic genomes of Mesocyclops edax, a freshwater cyclopoid copepod with a germline genome of ~15 Gb and a somatic genome of ~3 Gb. We show that most of the excised DNA consists of repetitive sequences that are either 1) verifiable transposable elements (TEs), or 2) non-simple repeats of likely TE origin. Repeat elements in both genomes are skewed towards younger (i.e. less divergent) elements. Excised DNA is a non-random sample of the germline repeat element landscape; younger elements, and high frequency DNA transposons and LINEs, are disproportionately eliminated from the somatic genome. Our results suggest that germline genome expansion in M. edax reflects explosive repeat element proliferation, and that billions of base pairs of such repeats are deleted from the somatic genome every generation. Thus, we hypothesize that chromatin diminution is a mechanism that controls repeat element load, and that this load can evolve to be divergent between tissue types within single organisms.

Transcriptional Profiling of Metabolic Transitions during Development and Diapause Preparation in the Copepod Calanus finmarchicus.

Science.gov (United States)

Tarrant, Ann M; Baumgartner, Mark F; Lysiak, Nadine S J; Altin, Dag; Størseth, Trond R; Hansen, Bjørn Henrik

2016-12-01

Calanus finmarchicus, like many other copepods in the family Calanidae, can enter into a facultative diapause during the last juvenile phase (fifth copepodid, C5) to enable survival during unfavorable periods. Diapause is essential to the persistence of Calanus populations and profoundly impacts energy flow within oceanic ecosystems, yet regulation of diapause is not understood in these animals. Transcriptional profiling has begun to provide insight into metabolic changes occurring as C. finmarchicus prepares for and enters into diapause or skips diapause to prepare for the terminal molt. In particular, components of the glycolysis, pentose phosphate and lipid synthesis pathways are upregulated early in the C5 stage when lipid stores are low. Currently, our ability to identify metabolic patterns is limited by the incomplete functional annotation of the C. finmarchicus transcriptome. Such limitations are widespread among studies of non-model organisms and addressing them should be a priority for future research. In addition, integrating the results across multiple emerging complementary transcriptomic studies will provide a more complete picture of copepod physiology than isolated studies. Ultimately, identifying molecular markers of copepod physiology could enable robust identification of animals preparing to enter into diapause and ultimately lead to a greatly improved understanding of diapause regulation. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Mating success and sexual selection in a pelagic copepod, Temora longicornis: Evidence from paternity analyses

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Eg Nielsen, Einar; Thygesen, Uffe Høgsbro

2015-01-01

Knowledge about mating patterns is essential for understanding and explaining rates of reproduction and genetic potential of copepods populations. The aim of this study was to examine (1) the occurrence of multiple paternity in Temora longicornis, (2) the effect of multiple paternity (if present......) on the females reproductive output, and (3) whether mating is random or some individuals have a higher than average chance of fertilizing or being fertilized (super individuals). We show that multiple paternity is common in this copepod species, that females benefit from multiple matings by increased offspring...... production, and that a relatively small fraction of the males and females in a population account for most of the offspring production. In both males and females, mating is nonrandom. Superior individuals with a higher than average matings success were identified both among females and among males....

Genome-wide identification of whole ATP-binding cassette (ABC) transporters in the intertidal copepod Tigriopus japonicus.

Science.gov (United States)

Jeong, Chang-Bum; Kim, Bo-Mi; Lee, Jae-Seong; Rhee, Jae-Sung

2014-08-05

The ATP-binding cassette (ABC) transporter superfamily is one of the largest transporter gene families and is observed in all animal taxa. Although a large set of transcriptomic data was recently assembled for several species of crustaceans, identification and annotation of the large ABC transporter gene family have been very challenging. In the intertidal copepod Tigriopus japonicus, 46 putative ABC transporters were identified using in silico analysis, and their full-length cDNA sequences were characterized. Phylogenetic analysis revealed that the 46 T. japonicus ABC transporters are classified into eight subfamilies (A-H) that include all the members of all ABC subfamilies, consisting of five ABCA, five ABCB, 17 ABCC, three ABCD, one ABCE, three ABCF, seven ABCG, and five ABCH subfamilies. Of them, unique isotypic expansion of two clades of ABCC1 proteins was observed. Real-time RT-PCR-based heatmap analysis revealed that most T. japonicus ABC genes showed temporal transcriptional expression during copepod development. The overall transcriptional profile demonstrated that half of all T. japonicus ABC genes were strongly associated with at least one developmental stage. Of them, transcripts TJ-ABCH_88708 and TJ-ABCE1 were highly expressed during all developmental stages. The whole set of T. japonicus ABC genes and their phylogenetic relationships will provide a better understanding of the comparative evolution of essential gene family resources in arthropods, including the crustacean copepods.

The metabolic response of marine copepods to environmental warming and ocean acidification in the absence of food

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Mayor, Daniel J.; Sommer, Ulf; Cook, Kathryn B.; Viant, Mark R.

2015-09-01

Marine copepods are central to the productivity and biogeochemistry of marine ecosystems. Nevertheless, the direct and indirect effects of climate change on their metabolic functioning remain poorly understood. Here, we use metabolomics, the unbiased study of multiple low molecular weight organic metabolites, to examine how the physiology of Calanus spp. is affected by end-of-century global warming and ocean acidification scenarios. We report that the physiological stresses associated with incubation without food over a 5-day period greatly exceed those caused directly by seawater temperature or pH perturbations. This highlights the need to contextualise the results of climate change experiments by comparison to other, naturally occurring stressors such as food deprivation, which is being exacerbated by global warming. Protein and lipid metabolism were up-regulated in the food-deprived animals, with a novel class of taurine-containing lipids and the essential polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid and docosahexaenoic acid, changing significantly over the duration of our experiment. Copepods derive these PUFAs by ingesting diatoms and flagellated microplankton respectively. Climate-driven changes in the productivity, phenology and composition of microplankton communities, and hence the availability of these fatty acids, therefore have the potential to influence the ability of copepods to survive starvation and other environmental stressors.

Sensory capabilities and food capture of two small copepods, Paracalanus parvus and Pseudocalanus sp

DEFF Research Database (Denmark)

Tiselius, Peter; Saiz, Enric; Kiørboe, Thomas

2013-01-01

intermittently and lasted 215–227 ms. The weak feeding current and fast response of the copepods allowed ample time for detection of cells entrained in the feeding current and no distant olfaction was observed. Modeled effect of cell size on cell surface concentration of cue chemicals show that only cells...... distance, but larger prey caused a significantly longer handling time. Post-detection processing of the cells was exceedingly fast. The time from detection to the cell being placed at the mouth lasted 35 ± 19 ms and rejection of unwanted cells 61 ± 21 ms. Grooming of antennules and carapace occurred...... with a radius larger than ∼ 15 µm may be detected chemically and that only very much larger and/or very leaky cells can be detected at distance. Copepods have elaborate and exceedingly fast handling techniques that allow effective prey detection and capture, but there is no evidence of remote chemically...

SWIMMING BEHAVIOR OF DEVELOPMENTAL STAGES OF THE CALANOID COPEPOD TEMORA-LONGICORNIS AT DIFFERENT FOOD CONCENTRATIONS

NARCIS (Netherlands)

VANDUREN, LA; VIDELER, JJ

1995-01-01

The swimming behaviour of developmental stages of the marine calanoid copepod Temora longicornis was studied using 2-dimensional observations under a microscope and a 3-dimensional filming technique to analyze swimming mode, swimming speed and swimming trajectories under different food

Aldehyde suppression of copepod recruitment in blooms of a ubiquitous planktonic diatom

Science.gov (United States)

Ianora, Adrianna; Miralto, Antonio; Poulet, Serge A.; Carotenuto, Ylenia; Buttino, Isabella; Romano, Giovanna; Casotti, Raffaella; Pohnert, Georg; Wichard, Thomas; Colucci-D'Amato, Luca; Terrazzano, Giuseppe; Smetacek, Victor

2004-05-01

The growth cycle in nutrient-rich, aquatic environments starts with a diatom bloom that ends in mass sinking of ungrazed cells and phytodetritus. The low grazing pressure on these blooms has been attributed to the inability of overwintering copepod populations to track them temporally. We tested an alternative explanation: that dominant diatom species impair the reproductive success of their grazers. We compared larval development of a common overwintering copepod fed on a ubiquitous, early-blooming diatom species with its development when fed on a typical post-bloom dinoflagellate. Development was arrested in all larvae in which both mothers and their larvae were fed the diatom diet. Mortality remained high even if larvae were switched to the dinoflagellate diet. Aldehydes, cleaved from a fatty acid precursor by enzymes activated within seconds after crushing of the cell, elicit the teratogenic effect. This insidious mechanism, which does not deter the herbivore from feeding but impairs its recruitment, will restrain the cohort size of the next generation of early-rising overwinterers. Such a transgenerational plant-herbivore interaction could explain the recurringly inefficient use of a predictable, potentially valuable food resource-the spring diatom bloom-by marine zooplankton.

Copepod community along the Mediterranean coast of Morocco (Southwestern Alboran Sea during spring

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A. BERRAHO

2016-09-01

Full Text Available Copepod community along the Mediterranean Moroccan coast was investigated, for the first time, during April 2013. Total abundance varied from 53 to 4557 ind. m-3 and high values were found in coastal waters. Oithona nana and Paracalanus parvus dominated in the entire area and species diversity was decreasing from the West to the East. Hierarchical clustering revealed three groups of stations, depending on their geographic position (western, central and eastern areas. Indicator species analysis pointed out that Clausocalanus furcatus and Gaetanus sp. were significantly associated with Group I, Clausocalanus sp., Centropages sp. and Centropages chierchiae with Group II, whereas Temora longicornis was significantly associated with Group III. Detrended Correspondence Analysis based on the species abundance and environmental variables (temperature, salinity, chlorophyll-a, highlighted a more or less similar setting of stations which was related to salinity and temperature. The presence of three anticyclonic gyres at the northern part of the study area is suggested as the major factor acting on the variability of copepod community along the Mediterranean Moroccan coast.

Copepod community growth rates in relation to body size, temperature, and food availability in the East China Sea: a test of metabolic theory of ecology

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K. Y. Lin

2013-03-01

Full Text Available Zooplankton play an essential role in marine food webs, and understanding how community-level growth rates of zooplankton vary in the field is critical for predicting how marine ecosystem function may vary in the face of environmental changes. Here, we used the artificial cohort method to examine the effects of temperature, body size, and chlorophyll concentration (a proxy for food on weight-specific growth rates for copepod communities in the East China Sea. Specifically, we tested the hypothesis that copepod community growth rates can be described by the metabolic theory of ecology (MTE, linking spatio-temporal variation of copepod growth rate with temperature and their body size. Our results generally agree with predictions made by the MTE and demonstrate that weight-specific growth rates of copepod communities in our study area are positively related with temperature and negatively related to body size. However, the regression coefficients of body size do not approach the theoretical predictions. Furthermore, we find that the deviation from the MTE predictions may be partly attributed to the effect of food availability (which is not explicitly accounted for by the MTE. In addition, significant difference in the coefficients of temperature and body size exists among taxonomic groups. Our results suggest that considering the effects of food limitation and taxonomy is necessary to better understand copepod growth rates under in situ conditions, and such effects on the MTE-based predictions need further investigation.

Effects of a La Niña event on hydrological patterns and copepod community structure in a shallow tropical estuary (Taperaçu, Northern Brazil)

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Andrade, Marcela P.; Magalhães, André; Pereira, Luci C. C.; Flores-Montes, Manuel J.; Pardal, Emarielle C.; Andrade, Thamara P.; Costa, Rauquírio M.

2016-12-01

The influences of the 2011 La Niña event on the hydrological patterns and copepod community structure were investigated in a shallow tropical estuary, the Taperaçu, in northern Brazil. Specifically, this study aimed to explore the response of the most dominant copepod species and ecological indices (diversity, evenness and richness) to temporal changes in rainfall regime and water parameters in a tropical meso-macro tidal setting. Zooplankton samples were collected from three sampling sites using a conical plankton net (120 μm mesh), with both water and zooplankton samples analyzed by standard methods. In 2011, the physical, chemical and biological parameters of the water were exacerbated by increased rainfall levels resulting from the La Niña event. This resulted in a reduction in the salinity and an increase in dissolved nutrient concentrations and phytoplankton biomass in the study area. These conditions had a direct effect on the monthly dynamics of copepods as a whole, and in particular of five species, O. oswaldocruzi (169,090 ± 254,609 ind. m- 3; p 0.05), O. hebes (40,888 ± 64,893 ind. m- 3; p 0.05), all of which were represented by higher densities in February. An extremely high recruitment rate of copepod nauplii was also observed during this month (3,088,309 ± 5,206,645 ind. m- 3; p copepod community, but may also have provoked shifts in trophic dynamics at higher levels, such as zooplanktivorous fishes.

CellTracker Green labelling vs. rose bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes

Directory of Open Access Journals (Sweden)

M. Grego

2013-07-01

Full Text Available Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week in the northern Adriatic Sea (Mediterranean and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG – new labelling approach for meiofauna – with the traditional rose bengal (RB staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as it does live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more precise quantification of community degradation, especially after an oxygen depletion event, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

Potential of the small cyclopoid copepod Paracyclopina nana as an invertebrate model for ecotoxicity testing.

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Dahms, Hans-Uwe; Won, Eun-Ji; Kim, Hui-Su; Han, Jeonghoon; Park, Heum Gi; Souissi, Sami; Raisuddin, Sheikh; Lee, Jae-Seong

2016-11-01

Aquatic invertebrates contribute significantly to environmental impact assessment of contaminants in aquatic ecosystems. Much effort has been made to identify viable and ecologically relevant invertebrate test organisms to meet rigorous regulatory requirements. Copepods, which are ecologically important and widely distributed in aquatic organisms, offer a huge opportunity as test organisms for aquatic toxicity testing. They have a major role not only in the transfer of energy in aquatic food chains, but also as a medium of transfer of aquatic pollutants across the tropic levels. In this regard, a supratidal and benthic harpacticoid copepod Tigriopus japonicus Mori (order Harpacticoida) has shown promising characteristics as a test organism in the field of ecotoxicology. Because there is a need to standardize a battery of test organisms from species in different phylogenetic and critical ecosystem positions, it is important to identify another unrelated planktonic species for wider application and comparison. In this regard, the cyclopoid copepod Paracyclopina nana Smirnov (order Cyclopoida) has emerged as a potential test organism to meet such requirements. Like T. japonicus, it has a number of features that make it a candidate worth consideration in such efforts. Recently, the genomics of P. nana has been unraveled. Data on biochemical and molecular responses of P. nana against exposure to environmental chemicals and other stressors have been collected. Recently, sequences and expression profiles of a number of genes in P. nana encoding for heat shock proteins, xenobiotic-metabolizing enzymes, and antioxidants have been reported. These genes serve as potential biomarkers in biomonitoring of environmental pollutants. Moreover, the application of gene expression techniques and the use of its whole transcriptome have allowed evaluation of transcriptional changes in P. nana with the ultimate aim of understanding the mechanisms of action of environmental stressors

Identification of the Full 46 Cytochrome P450 (CYP) Complement and Modulation of CYP Expression in Response to Water-Accommodated Fractions of Crude Oil in the Cyclopoid Copepod Paracyclopina nana.

Science.gov (United States)

Han, Jeonghoon; Won, Eun-Ji; Kim, Hui-Su; Nelson, David R; Lee, Su-Jae; Park, Heum Gi; Lee, Jae-Seong

2015-06-02

The 46 cytochrome P450 (CYP) gene superfamily was identified in the marine copepod Paracyclopina nana after searching an RNA-seq database and comparing it with other copepod CYP gene families. To annotate the 46 Pn-CYP genes, a phylogenetic analysis of CYP genes was performed using a Bayesian method. Pn-CYP genes were separated into five different clans: CYP2, CYP3, CYP20, CYP26, and mitochondrial. Among these, the principal Pn-CYP genes involved in detoxification were identified by comparing them with those of the copepod Tigriopus japonicus and were examined with respect to their responses to exposure to a water-accommodated fraction (WAF) of crude oil and to the alkylated forms of two polycyclic aromatic hydrocarbons (PAHs; phenanthrene and fluorene). The expression of two Pn-CYP3027 genes (CYP3027F1 and CYP3027F2) was increased in response to WAF exposure and also was upregulated in response to the two alkylated PAHs. In particular, Pn-CYP3027F2 showed the most notable increase in response to 80% WAF exposure. These two responsive CYP genes (Pn-CYP3027F1 and CYP3027F2) were also phylogenetically clustered into the same clade of the WAF- and alkylated PAH-specific CYP genes of the copepod T. japonicus, suggesting that these CYP genes would be those chiefly involved in detoxification in response to WAF exposure in copepods. In this paper, we provide information on the copepod P. nana CYP gene superfamily and also speculate on its potential role in the detoxification of PAHs in marine copepods. Despite the nonlethality of WAF, Pn-CYP3027F2 was rapidly and significantly upregulated in response to WAF that may serve as a useful biomarker of 40% or higher concentration of WAF exposure. This paper will be helpful to better understand the molecular mechanistic events underlying the metabolism of environmental toxicants in copepods.

Propagation of planktonic copepods: production and mortality of eggs

DEFF Research Database (Denmark)

Kiørboe, Thomas; Møhlenberg, Flemming; Tiselius, Peter

1988-01-01

Data on fecundity and egg mortality of neritic copepods were collected in various seasons, areas and under various hydrographical conditions. On a seasonal basis variations in fecundity (F) were related to temperature rather than to the abundance of phytoplankton (P). However, a strong correlation...... between F and P was evident when water column stability varied horisontally or temporally (i.e. at a tidal front or subsequent to a storm). Estimated specific egg-mortalities were variable and occasionally very severe, up to 9.1 d−1, implying that down to 10−4% of the eggs survive to hatching...

First insights into genus level diversity and biogeography of deep sea benthopelagic calanoid copepods in the South Atlantic and Southern Ocean

Science.gov (United States)

Renz, Jasmin; Markhaseva, Elena L.

2015-11-01

Calanoid copepods constitute the most numerous organisms not only in the pelagic realm, but also in the benthic boundary layer, which gives them an important role in the turnover of organic matter in the benthopelagic habitat. During seven expeditions to the South Atlantic and Southern Ocean, the diversity and biogeography of deep-sea benthopelagic calanoid copepods were studied. The communities of calanoids living in the vicinity of the seabed were characterized by high diversity comparable to many pelagic habitats, but low abundance of individuals. Members of the taxon Clausocalanoidea dominated the communities, and within this taxon most individuals belonged to detritivore calanoids characterized by sensory setae on the second maxillae or aetideid copepods. 73% of all genera classified as obligate or predominantly benthopelagic copepods detected during these expeditions were new to science and a vast number of genera and species have been described since then. Comparing the communities of calanoid genera between different regions, the assemblages in the Southern Ocean differed significantly from the Southeast and Southwest Atlantic. A latitudinal diversity gradient could be observed, with highest numbers of genera in the Southwest Atlantic and low numbers at stations in the Southern Ocean. Reviewing the literature, endemism for benthopelagic calanoids appeared to be low on a latitudinal range caused by connectivity in benthopelagic habitats through spreading water masses. However, considering the habitats structuring the water column vertically, a high number of genera are endemic in the benthopelagial and specialized to living within the vicinity of the seabed.

Impacts of temperature and crowding on sex ratio, fecundity and Wolbachia infection intensity in the copepod, Mesocyclops thermocyclopoides.

Science.gov (United States)

Wiwatanaratanabutr, Itsanun; Grandjean, Frederic

2016-11-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in arthropods. Here, we describe the effects of two environmental factors (crowding and temperature) on phenotypic expression of feminization, the host's fecundity and Wolbachia infection intensity among life cycle stages in the naturally Wolbachia-infected copepod, Mesocyclops thermocyclopoides. The copepod was first found to be co-infected with Wolbachia A- and B-supergroups Wolbachia strains based on wsp primers. The relative Wolbachia infection intensity within individuals was determined using quantitative real-time PCR and was significantly higher in the B-supergroup than in the A-supergroup. Experimental results of temperature effect on bacterial density in each developmental stage revealed a significant decrease in Wolbachia infection intensity following exposure to high temperature (37°C) in both sexes and implied that Wolbachia might survive in room temperature (25°C) better than in high temperature. Experimental results of crowding effects on Wolbachia infection intensity suggested a negative correlation between copepod nauplii and Wolbachia infection intensity. No effect of rearing temperature on the sex ratio was reported although the fecundity was significantly decreased by high temperature. The results showed that Wolbachia infection intensity to be correlated with crowding conditions and was decreased following exposure of elevated temperature. Copyright © 2016 Elsevier Inc. All rights reserved.

Dissonus pastinum n. sp. (Siphonostomatoida: Dissonidae), a copepod parasitic on a horn shark from Japan

NARCIS (Netherlands)

Deets, Gregory B.; Dojiri, Masahiro

1990-01-01

A new species of siphonostomatoid copepod, Dissonus pastinum, is described from the horn shark, Heterodontus japonicus (Dumeril), from Awa, Japan. The new species differs from all congeners except D. ruvetti Nunes-Ruivo & Fourmanoir, 1956 and D. nudiventris Kabata, 1965 by the presence of the

Use of flubendazole as a therapeutic agent against rotifers (Brachionus plicatilis) in intensive cultures of the harpacticoid copepod Tisbe holothuriae

DEFF Research Database (Denmark)

Steenfeldt, Svend Jørgen; Nielsen, Johan W.

2010-01-01

down production and subsequently use a therapeutic agent to eliminate all zooplankton in the system before restart with a stock culture free of rotifers. We tested flubendazole as a mean of controlling rotifers (Brachionus plicatilis) in intensive laboratory cultures of the harpacticoid copepod (Tisbe...... holothuria). Flubendazole was lethal to rotifers in concentrations as low as 0.05 mg L−1. There was no significant effect on the concentration of copepods, even at the highest concentration tested, i.e. 5.0 mg L−1 flubendazole. We conclude that flubendazole is an effective drug for control of B. plicatilis...

Bioaccumulation and physiological effects of copepods sp. (Eucyclop sp.) fed Chlorella ellipsoides exposed to titanium dioxide (TiO2) nanoparticles and lead (Pb2+).

Science.gov (United States)

Matouke, Moise M; Mustapha, Moshood

2018-05-01

The demand for manufactured products and the derivatives of nanomaterials and non essential metals continue to increase, and as a consequence their presence in fisheries and aquaculture has therefore become a major concern for the risks to which our environment is exposed. The bioaccumulation profile of binary compounds (Titanium dioxide nanoparticles and lead) and their effects on the feeding behaviour of copepods were assessed in a simplified food chain including, the freshwater alga Chlorella ellipsoides and the cyclopoids copepods sp. Our results indicated that Pb and TiO 2 NPs individually and mixed can be transferred from alga to copepods via dietary pathway. The highest bioconcentration factor (748.5) was recorded for Pb in the combined compounds (Pb15 + Ti16.5) μg L -1 and the highest BCF (5.57) recorded for TiO 2 NPs was found in TiO 2 NPs (16.5) alone. Ingestion and filtration rate decreased significantly (p  0.05) in both single and binary treatments. The results demonstrate that the co-exposure of TiO 2 NPs and Pb inhibit the ingestion and filtration of microalgae by cyclopoid copepods sp. and also induce increase of carbohydrate, lipid; GPx, GR and CAT due to stress. Copyright © 2018. Published by Elsevier B.V.

Spatial patterns of littoral zooplankton assemblages along a salinity gradient in a brackish sea: A functional diversity perspective

Science.gov (United States)

Helenius, Laura K.; Leskinen, Elina; Lehtonen, Hannu; Nurminen, Leena

2017-11-01

The distribution patterns and diversity of littoral zooplankton are both key baseline information for understanding the functioning of coastal ecosystems, and for identifying the mechanisms by which the impacts of recently increased eutrophication are transferred through littoral food webs. In this study, zooplankton community structure and diversity along a shallow coastal area of the northern Baltic Sea were determined in terms of horizontal environmental gradients. Spatial heterogeneity of the zooplankton community was examined along the gradient. Altogether 31 sites in shallow sandy bays on the coast of southwest Finland were sampled in the summer periods of 2009 and 2010 for zooplankton and environmental variables (surface water temperature, salinity, turbidity, wave exposure, macrophyte coverage, chlorophyll a and nutrients). Zooplankton diversity was measured as both taxonomic as well as functional diversity, using trait-based classification of planktonic crustaceans. Salinity, and to a lesser extent turbidity and temperature, were found to be the main predictors of the spatial patterns and functional diversity of the zooplankton community. Occurrence of cyclopoid copepods, as well as abundances of the calanoid copepod genus Acartia and the rotifer genus Keratella were found to be key factors in differentiating sites along the gradient. As far as we know, this is the first extensive study of functional diversity in Baltic Sea coastal zooplankton communities.

Distinctly different behavioral responses of a copepod, Temora longicornis, to different strains of toxic dinoflagellates, Alexandrium spp

DEFF Research Database (Denmark)

Xu, Jiayi; Hansen, Per Juel; Nielsen, Lasse Tor

2017-01-01

Zooplankton responses to toxic algae are highly variable, even towards taxonomically closely related species or different strains of the same species. Here, the individual level feeding behavior of a copepod, Temora longicornis, was examined which offered 4 similarly sized strains of toxic...... of the copepod during 4 h incubations: (i) the ‘normal’ feeding behavior, in which the feeding appendages were beating almost constantly to produce a feeding current and most (90%) of the captured algae were ingested; (ii) the beating activity of the feeding appendages was reduced by ca. 80% during the initial...... may be equally beneficial to the prey and its competitors. These behaviors were not related to lytic activity or overall paralytic shellfish toxins (PSTs) content and composition and suggest that other cues are responsible for the responses....

Tidal influence on the distribution of hydrophobic organic contaminants in the Seine Estuary and biomarker responses on the copepod Eurytemora affinis

Energy Technology Data Exchange (ETDEWEB)

Cailleaud, K. [Universite Bordeaux 1, CNRS, ISM-LPTC-UMR 5255, Laboratory of Physico- and Toxico-Chemistry, 351 Cours de la Liberation, 33405 Talence (France) and Universite des Sciences et Technologies de Lille - Lille 1, Laboratoire d' Oceanologie et de Geosciences, UMR CNRS 8187 LOG, Station Marine de Wimereux, 28 Avenue Foch, 62930 Wimereux (France) and Faculte des Sciences et Techniques du Havre, LEMA-UPRES EA3222, Laboratoire d' Ecotoxicologie-Milieux Aquatiques, GDR IMOPHYS, 25 rue Philippe Lebon, 76058 Le Havre (France); Forget-Leray, J. [Faculte des Sciences et Techniques du Havre, LEMA-UPRES EA3222, Laboratoire d' Ecotoxicologie-Milieux Aquatiques, GDR IMOPHYS, 25 rue Philippe Lebon, 76058 Le Havre (France); Peluhet, L.; LeMenach, K. [Universite Bordeaux 1, CNRS, ISM-LPTC-UMR 5255, Laboratory of Physico- and Toxico-Chemistry, 351 Cours de la Liberation, 33405 Talence (France); Souissi, S. [Universite des Sciences et Technologies de Lille - Lille 1, Laboratoire d' Oceanologie et de Geosciences, UMR CNRS 8187 LOG, Station Marine de Wimereux, 28 Avenue Foch, 62930 Wimereux (France); Budzinski, H. [Universite Bordeaux 1, CNRS, ISM-LPTC-UMR 5255, Laboratory of Physico- and Toxico-Chemistry, 351 Cours de la Liberation, 33405 Talence (France)], E-mail: h.budzinski@ism.u-bordeaux1.fr

2009-01-15

To elucidate tidally related variations of hydrophobic organic contaminant (HOC) bioavailability and the impact of these contaminants on estuarine ecosystems, both PCB and PAH concentrations were investigated in the dissolved phase and in the suspended particulate material (SPM) of the Seine Estuary. Both PAH and PCB highest levels were observed in surface and bottom water when SPM remobilizations were maximum, in relation to higher speed currents. In parallel, acetylcholinesterase (AChE) and glutathione-S-transferase (GST) activities were investigated in the copepod Eurytemora affinis. Significant decreasing AChE levels were measured during the tidal cycle and between surface and bottom copepods related to salinity and to HOC concentration variations. Significant increasing GST levels were also observed when HOC concentrations in the water column were the highest. This study underlined the need to standardize sampling procedures for biomonitoring studies in order to avoid interfering factors that could modify biomarker responses to chemical exposure. - Variations of contamination of E. affinis and enzymatic responses have been studied over a tide cycle in view to improve the use of this copepod for biomonitoring.

Tidal influence on the distribution of hydrophobic organic contaminants in the Seine Estuary and biomarker responses on the copepod Eurytemora affinis

International Nuclear Information System (INIS)

Cailleaud, K.; Forget-Leray, J.; Peluhet, L.; LeMenach, K.; Souissi, S.; Budzinski, H.

2009-01-01

To elucidate tidally related variations of hydrophobic organic contaminant (HOC) bioavailability and the impact of these contaminants on estuarine ecosystems, both PCB and PAH concentrations were investigated in the dissolved phase and in the suspended particulate material (SPM) of the Seine Estuary. Both PAH and PCB highest levels were observed in surface and bottom water when SPM remobilizations were maximum, in relation to higher speed currents. In parallel, acetylcholinesterase (AChE) and glutathione-S-transferase (GST) activities were investigated in the copepod Eurytemora affinis. Significant decreasing AChE levels were measured during the tidal cycle and between surface and bottom copepods related to salinity and to HOC concentration variations. Significant increasing GST levels were also observed when HOC concentrations in the water column were the highest. This study underlined the need to standardize sampling procedures for biomonitoring studies in order to avoid interfering factors that could modify biomarker responses to chemical exposure. - Variations of contamination of E. affinis and enzymatic responses have been studied over a tide cycle in view to improve the use of this copepod for biomonitoring

Harpacticoid copepod diversity at two physically reworked sites in the deep sea

Science.gov (United States)

Thistle, David

1998-01-01

Grassle's and Jumars' theories of diversity maintenance in the quiescent deep sea view millimeter-to-meter-scale patchiness (mostly of biological origin) as crucial. In other deep-sea regions, episodes of strong near-bottom flow put the surficial sediment layers into motion, obliterating the biologically produced, millimeter-to-meter-scale patchiness. Under these theories, sites eroded so frequently that such patchiness is eliminated almost as soon as it is created should have lower diversities than sites where the time between erosive events is sufficient for this type of patchiness to be produced and exploited. I tested this prediction by comparing the diversities of harpacticoid copepods at two sites on Fieberling Guyot to determine whether Grassle's and Jumars' theories can be extended to the portion of the deep sea that experiences episodic erosive flows. At White Sand Swale (=WSS) (32°27.581'N, 127°47.839'W), strong near-bottom flows erode the surficial sediment daily. At Sea Pen Rim (=SPR) (32°27.631'N, 127°49.489'W), strong near-bottom flows erode the surficial sediment a few times annually. Contrary to expectation, the diversity of harpacticoid copepods was significantly greater at WSS than at SPR. However, the erosion regime at WSS may create small-scale patchiness that promotes harpacticoid diversity.

Ecotoxicity of triphenyltin on the marine copepod Tigriopus japonicus at various biological organisations: from molecular to population-level effects.

Science.gov (United States)

Yi, Andy Xianliang; Han, Jeonghoon; Lee, Jae-Seong; Leung, Kenneth M Y

2014-09-01

Triphenyltin compounds (TPTs), as effective biocides for different industrial and agricultural purposes, have been detected in coastal marine environments worldwide, in particular in Asian countries. However, little is known about their toxicity to marine organisms. This study comprehensively investigated the molecular, individual and population responses of the marine copepod, Tigriopus japonicus upon waterborne exposure to TPT chloride (TPTCl). Our results indicated that TPTCl was highly toxic to adult T. japonicus, with a 96-h LC50 concentration at 6.3 μg/L. As shown in a chronic full life-cycle test, T. japonicus exposed to 1.0 μg/L TPTCl exhibited a delay in development and a significant reduction of population growth, in terms of the intrinsic rate of increase (r m ). Based on the negative relationship between the r m and exposure concentration, a critical effect concentration was estimated at 1.6 μg/L TPTCl; at or above which population extinction could occur. At 0.1 μg/L TPTCl or above, the sex ratio of the second generation of the copepod was significantly altered and changed to a male-biased population. At molecular level, the inhibition of the transcriptional expression of glutathione S-transferase related genes might lead to dysfunction of detoxification, and the inhibition of retinoid X receptor mRNA expression implied an interruption of the growth and moulting process in T. japonicus. As the only gene that observed up-regulated in this study, the expression of heat shock protein 70 (hsp70) increased in a concentration-dependent manner, indicating its function in protecting the copepod from TPT-mediated oxidative stress. The study advances our understanding on the ecotoxicity of TPT, and provides some initial data on its toxic mechanisms in small crustaceans like copepods.

Foraging mode and prey size spectra of suspension-feeding copepods and other zooplankton

DEFF Research Database (Denmark)

Kiørboe, Thomas

2016-01-01

Prey size spectra of suspension-feeding zooplankton may be predicted from foraging mode and a mechanistic understanding of prey perception and capture. I examine this for suspension-feeding copepods where 2 foraging modes can be distinguished: ambush feeding and active (i.e. cruising and feeding-...... the prediction. I also make qualitative predictions of food size spectra in zooplankton with other prey perception mechanisms that accord with observations....

Role of lipids for the reproductive success of the Arctic copepod Calanus glacialis

Science.gov (United States)

Hatlebakk, M. K.; Graeve, M.; Niehoff, B.; Johnsen, G.; Søreide, J.

2016-02-01

Extensive energy storage is common among polar animals, and a range of reproductive strategies have evolved from pure capital breeders, relying on stored energy only, to 100% income breeders where freshly ingested food fuel reproduction. The Arctic calanoid copepod Calanus glacialis is primarily a grazer that accumulates large lipid stores during spring and summer. The breeding strategy to this relatively large and lipid-rich copepod is somewhere on the continuum from pure capital to 100% income breeder. To investigate the importance of stored lipids versus freshly ingested food for the reproductive success of this key copepod we conducted a combined laboratory and field study on a high-Arctic population of C. glacialis in Svalbard from January to May. Total lipids, lipid composition, gonad maturation, egg production and egg hatching success were carefully followed for starved and algal fed females in the laboratory and for females in situ. Lipid stores decreased significantly over time even when food was available, both in laboratory and in field, suggesting that the females largely depended on stored resources for reproduction no matter of the food availability. Lipid reduction was most rapid during gonad maturation prior to first egg production. Almost all fed females spawned compared to only half of the starved ones, and number of eggs and the egg hatching success were significantly improved for fed females. When food was scarce, females produced fewer but more lipid-rich eggs as opposed to more eggs with less lipids when food was abundant - a strategy not previously described for C. glacialis. The fatty acid composition appeared to be more important than the total lipid content for ensuring high egg hatching success, and the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3), as well as the saturated fatty acids 16:0 and 18:0 seemed to be particularly important. We conclude that C. glacialis is capable of capital breeding, but primarily rely on fresh food for

Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

NARCIS (Netherlands)

Kouwenberg, Juliana H.M.

1993-01-01

Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish

Effects of three PBDEs on development, reproduction and population growth rate of the harpacticoid copepod Nitocra spinipes

International Nuclear Information System (INIS)

Breitholtz, Magnus; Wollenberger, Leah

2003-01-01

The current knowledge concerning effects of polybrominated diphenyl ethers (PBDEs) on aquatic organisms is very limited. A full life-cycle (≤26 days exposure) ecotoxicity test with the particle-feeding copepod Nitocra spinipes was therefore used to study effects of BDE-47, -99 and -100 on larval development rate (LDR) and population growth rate (r m ). LDR significantly decreased in copepods exposed for 6 days to nominal concentrations ≥0.013 mg/l BDE-47 and ≥0.03 mg/l BDE-99. Large concentration ratios (≤338) between adult acute and juvenile subchronic endpoints were observed. Exposure over the full life cycle (≤26 days) showed that r m in general was a less sensitive endpoint than LDR. Still, the r m in copepods exposed to 0.04 mg/l BDE-47 was significantly reduced compared to the controls (***P 14 C-BDE-47 and 14 C-BDE-99 in the test system showed that the major fractions (∼50-80%) were associated to particulate material. Our findings indicate that development and reproduction in N. spinipes are sensitive to the tested PBDEs and that ingestion of particle-adsorbed PBDEs most likely is the predominant route of exposure in N. spinipes. However, to further improve the usefulness of laboratory effect levels of PBDEs and other lipophilic substances for environmental risk assessment, it is important to develop ecotoxicological tools, which can evaluate and rate the toxic contribution from different matrices, such as suspended particles, sediment, food, water etc

Diel vertical migration of copepods in a Brazilian lake: a mechanism for decreasing risk of Chaoborus predation?

Directory of Open Access Journals (Sweden)

Perticarrari A.

Full Text Available A comparison between two studies on diel vertical migration of two cyclopoid copepod species, in Lake Monte Alegre, undertaken in 1985/86 and 1999, revealed a change in their migratory behavior. In summer, during a period of marked stratification with low dissolved oxygen near the bottom, the organisms avoided the deepest layers, and migration was nocturnal or undetectable, in both periods. On other occasions, with partial or total circulation in the lake, a weak twilight migration of copepodites and adults in 1985 was replaced by the reverse in 1999. Differences were found among stages, with the weakest or undetectable migration being observed for nauplii. The migratory pattern change for copepodites and adults might be related with a recent predation pressure increase by Chaoborus larvae on copepods, after the virtual disappearance of their main cladoceran prey.

Scaling of fecundity, growth and development in marine planktonic copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas; Sabatini, M.

1995-01-01

We compiled information from the literature on female and egg sizes and maximum egg production, growth and developmental rates in marine planktonic copepods. While specific growth and developmental rates are invariant with body mass, weight- specific fecundity scales with female body mass(-0...... to 50% and have weight-specific fecundities that are 2.5 times and egg production rates that are 7.5 times those of the former, Nauplii develop faster (by a factor of 2) but grow slower (by 20 to 40%) than copepodites in both spawning types. The main demographic implications of these findings are (1...

Temporal and spatial changes in the copepod community during the 1974-1998 spring seasons in the Kuroshio region; a time period of profound changes in pelagic fish populations

Science.gov (United States)

Miyamoto, Hiroomi; Itoh, Hiroshi; Okazaki, Yuji

2017-10-01

The long-term change (1974-1998) of the pelagic copepod community in the Kuroshio region, western Pacific was examined in archival samples collected both day and night in April/May in a time period of profound changes in the pelagic fish populations. A total of 162 adult copepod species was found. The community analysis based on species composition and abundance of adult copepods identified five assemblages (A-E) by cluster analysis. These assemblages were distributed in the north-frontal area of the Kuroshio Current within the slope area (A), the Kuroshio axis area (B), the subtropical area (C, D), and the coastal area within the slope area (E), indicating that such diverse communities were formed to correspond with the gradual change in the oceanic environment across the Kuroshio Current. The abundance of copepods in the north-frontal area of the Kuroshio Current (A) was 1.6 times greater than that of the other assemblages. Kuroshio/subtropical species were abundant in the assemblage, suggesting that these species that were transported from the Kuroshio and/or subtropical regions increased in the slope region. Abundance and species richness of two assemblages (C, D), which were found in the subtropical areas were higher at night (C) than during the day (D), suggesting that diel vertical migration of copepods is one of the most important factors affecting changes in the community. Furthermore, a generalized additive model revealed that the most dominant subtropical/Kuroshio species increased in years in which the Kuroshio Current flowed further south, with the Kuroshio axis located far from the Japanese coast. In contrast, the model showed that the lower latitude of the Kuroshio axis positioned negatively affected coastal-dominant species, such as Paracalanus parvus sensu lato (s.l.). These results indicate that onshore-offshore shifts of the Kuroshio axis caused by Kuroshio meandering was an important factor involved in the inter-annual change in the copepod

Genome-wide identification of 52 cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus and their B[α]P-induced expression patterns.

Science.gov (United States)

Han, Jeonghoon; Kim, Duck-Hyun; Kim, Hui-Su; Nelson, David R; Lee, Jae-Seong

2017-09-01

Cytochrome P450s (CYPs) are enzymes with a heme-binding domain that are found in all living organisms. CYP enzymes have important roles associated with detoxification of xenobiotics and endogenous compounds (e.g. steroids, fatty acids, and hormones). Although CYP enzymes have been reported in several invertebrates, including insects, little is known about copepod CYPs. Here, we identified the entire repertoire of CYP genes (n=52) from whole genome and transcriptome sequences of the benthic copepod Tigriopus japonicus, including a tandem duplication (CYP3026A3, CYP3026A4, CYP3026A5), and examined patterns of gene expression over various developmental stages and in response to benzo[α]pyrene (B[α]P) exposure. Through phylogenetic analysis, the 52 T. japonicus CYP genes were assigned to five distinct clans: CYP2 (22 genes), CYP3 (19 genes), CYP4 (two genes), CYP20 (one gene), and mitochondrial (eight genes). Developmental stage and gender-specific expression patterns of the 52 T. japonicus CYPs were analyzed. CYP3022A1 was constitutively expressed during all developmental stages. CYP genes in clans 2 and 3 were induced in response to B[α]P, suggesting that these differentially modulated CYP transcripts are likely involved in defense against exposure to B[α]P and other pollutants. This study enhances our understanding of the repertoire of CYP genes in copepods and of their potential role in development and detoxification in copepods. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute and chronic toxicity study of the water accommodated fraction (WAF), chemically enhanced WAF (CEWAF) of crude oil and dispersant in the rock pool copepod Tigriopus japonicus.

Science.gov (United States)

Lee, Kyun-Woo; Shim, Won Joon; Yim, Un Hyuk; Kang, Jung-Hoon

2013-08-01

We determined the toxicity of the water accommodated hydrocarbon fraction (WAF), two chemically enhanced WAFs (CEWAFs; CEWAF-C, Crude oil+Corexit 9500 and CEWAF-H, Crude oil+Hiclean) of crude oil and two dispersants (Corexit 9500 and Hiclean) to the rock pool copepod Tigriopus japonicus. In the acute toxicity test, Corexit 9500 was the most toxic of all the chemicals studied. The nauplius stage of T. japonicus was more susceptible to the toxic chemicals studied than the adult female. The toxicity data using the nauplius stage was then considered as baseline to determine the spiking concentration of chemicals for chronic toxicity tests on the copepod. As the endpoints in the chronic toxicity test, survival, sex ratio, developmental time and fecundity of the copepod were used. All chemicals used in this study resulted in increased toxicity in the F1 generation. The lowest-observed-adverse-effect (LOAE) concentrations of WAF, CEWAF-H, CEWAF-C, Hiclean and Corexit 9500 were observed to be 50%, 10%, 0.1%, 1% and 1%, respectively. The results in present study imply that copepods in marine may be negatively influenced by spilled oil and dispersant. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physical control of the distributions of a key Arctic copepod in the Northeast Chukchi Sea

Science.gov (United States)

Elliott, Stephen M.; Ashjian, Carin J.; Feng, Zhixuan; Jones, Benjamin; Chen, Changsheng; Zhang, Yu

2017-10-01

The Chukchi Sea is a highly advective regime dominated by a barotropically driven northward flow modulated by wind driven currents that reach the bottom boundary layer of this shallow environment. A general northward gradient of decreasing temperature and food concentration leads to geographically divergent copepod growth and development rates between north and south. The physics of this system establish the biological connection potential between specific regions. The copepod Calanus glacialis is a key grazer, predator, and food source in Arctic shelf seas. Its summer distribution and abundance have direct effects on much of the food web, from phytoplankton to migrating bowhead whales. In August 2012 and 2013, C. glacialis distributions were quantified over Hanna Shoal in the northeast Chukchi Sea. Here an individual-based model with Lagrangian tracking and copepod life stage development capabilities is used to advect and develop these distributions forward and backward in time to determine the source (production locations) and sink (potential overwintering locations) regions of the transient Hanna Shoal C. glacialis population. Hanna Shoal supplies diapause competent C. glacialis to both the Beaufort Slope and the Chukchi Cap, mainly receives juveniles from the broad slope between Hanna Shoal and Herald Valley and receives second year adults from as far south as the Anadyr Gulf and as near as the broad slope between Hanna Shoal and Herald Valley. The 2013 sink region was shifted west relative to the 2012 region and the 2013 adult source region was shifted north relative to the 2012 adult source region. These connection potentials were not sensitive to precise times and locations of release, but were quite sensitive to depth of release. These patterns demonstrate how interannual differences in the physical conditions well south of Hanna Shoal play a critical role in determining the abundance and distribution of a key food source over Hanna Shoal and in the

Projected shifts in copepod surface communities in the Mediterranean Sea under several climate change scenarios

Science.gov (United States)

Benedetti, F.; Guilhaumon, F.; Adloff, F.; Irisson, J. O.; Ayata, S. D.

2016-02-01

Although future increases in water temperature and future changes in regional circulation are expected to have great impacts on the pelagic food-web, estimates focusing on community-level shifts are still lacking for the planktonic compartment. By combining statistical niche models (or species distribution models) with projections from a regional circulation model, the impact of climate change on copepod epipelagic communities is assessed for the Mediterranean Sea. Habitat suitability maps are generated for 106 of the most abundant copepod species to analyze emerging patterns of diversity at the community level. Using variance analysis, we also quantified the uncertainties associated to our modeling strategy (niche model choice, CO2 emission scenario, boundary forcings of the circulation model). Comparing present and future projections, changes in species richness (alpha diversity) and in community composition (beta diversity, decomposed into turnover and nestedness component) are calculated. Average projections show that copepod communities will mainly experience turn-over processes, with little changes in species richness. Species gains are mainly located in the Gulf of Lions, the Northern Adriatic and the Northern Aegean seas. However, projections are highly variable, especially in the Eastern Mediterranean basin. We show that such variability is mainly driven by the choice of the niche model, through interactions with the CO2 emission scenario or the boundary forcing of the circulation model can be locally important. Finally, the possible impact of the estimated community changes on zooplanktonic functional and phylogenetic diversity is also assessed. We encourage the enlargement of this type of study to other components of the pelagic food-web, and argue that niche models' outputs should always be given along with a measure of uncertainty, and explained in light of a strong theoretical background.

Effects of calanoid copepod Schmackeria poplesia as a live food on the growth, survival and fatty acid composition of larvae and juveniles of Japanese flounder, Paralichthys olivaceus

Science.gov (United States)

Liu, Guangxing; Xu, Donghui

2009-12-01

Zooplankton constitutes a major part of the diet for fish larvae in the marine food web, and it is generally believed that copepods can meet the nutritional requirements of fish larvae. In this study, calanoid copepod Schmackeria poplesia, rotifer Brachionus plicatilis and anostraca crustacean Artemia sp. were analyzed for fatty acid contents, and were used as live food for culturing larval Japanese flounder, Paralichthys olivaceus. The total content of three types of HUFAs (DHA, EPA and ARA) in S. poplesia was significantly higher than that in the other two live foods ( P<0.01). Three live organisms were used for raising larvae and juveniles of Paralichthys olivaceus respectively for 15 and 10 d. Then the growth, survival and fatty acid composition of the larvae and juveniles were investigated. The results showed that the larvae and juveniles fed with copepods ( S. poplesia) had significantly higher growth rate than those fed with the other two organisms ( P<0.01). The survival of the flounder larvae fed with copepods was significantly higher than that of the others ( P<0.01), and the survival of the juvenile fish fed with copepods was higher than that fed with Artemia ( P<0.05). The contents of three types of HUFAs (DHA, EPA and ARA) and the ratio of DHA/EPA in larval and juvenile flounder P. olivaceus were analyzed. The results showed that the contents of DHA, EPA and ARA in the larvae and juveniles fed with S. poplesia were higher than those fed with a mixed diet or Artemia only, and the ratio of EPA/ARA in larvae and juveniles of P. olivaceus fed with S. poplesia was lower than that in the case of feeding with a mixed diet or Artemia only. The present data showed that copepod is the best choice for feeding the larvae and juveniles of fish considering its effects on the survival, growth and nutrition composition of the fish.

First record of the Calanoid Copepod Pseudodiaptomus serricaudatus (Scott, T. 1894), (Copepoda: Calanoida: Pseudodiaptomidae) in the equatorial Indian ocean.

Digital Repository Service at National Institute of Oceanography (India)

Rebello, V.; Narvekar, J.; Gadi, P.; Venenkar, A.; Gauns, M.; PrasannaKumar, S.

, Pondicherry University, Port Blair, Andaman 3Happy Home Apartment, Near Canara Bank, Fatorda, Margao, Goa-403602 Abstract Pseudodiaptomus serricaudatus (Scott, T. 1894), a planktonic copepod belonging to the family Pseudodiaptomidae, though has...

Copepod faecal pellet transfer through the meso- and bathypelagic layers in the Southern Ocean in spring

Science.gov (United States)

Belcher, Anna; Manno, Clara; Ward, Peter; Henson, Stephanie A.; Sanders, Richard; Tarling, Geraint A.

2017-03-01

The faecal pellets (FPs) of zooplankton can be important vehicles for the transfer of particulate organic carbon (POC) to the deep ocean, often making large contributions to carbon sequestration. However, the routes by which these FPs reach the deep ocean have yet to be fully resolved. We address this by comparing estimates of copepod FP production to measurements of copepod FP size, shape, and number in the upper mesopelagic (175-205 m) using Marine Snow Catchers, and in the bathypelagic using sediment traps (1500-2000 m). The study is focussed on the Scotia Sea, which contains some of the most productive regions in the Southern Ocean, where epipelagic FP production is likely to be high. We found that, although the size distribution of the copepod community suggests that high numbers of small FPs are produced in the epipelagic, small FPs are rare in the deeper layers, implying that they are not transferred efficiently to depth. Consequently, small FPs make only a minor contribution to FP fluxes in the meso- and bathypelagic, particularly in terms of carbon. The dominant FPs in the upper mesopelagic were cylindrical and elliptical, while ovoid FPs were dominant in the bathypelagic. The change in FP morphology, as well as size distribution, points to the repacking of surface FPs in the mesopelagic and in situ production in the lower meso- and bathypelagic, which may be augmented by inputs of FPs via zooplankton vertical migrations. The flux of carbon to the deeper layers within the Southern Ocean is therefore strongly modulated by meso- and bathypelagic zooplankton, meaning that the community structure in these zones has a major impact on the efficiency of FP transfer to depth.

Extreme temperature and oil contamination shape the relative abundance of copepod species in the Arctic

DEFF Research Database (Denmark)

Dinh, Khuong Van; Nielsen, Torkel Gissel

is of north Atlantic origin. Pyrene is one of the most toxic components of crude oil to marine copepods. The temperatures of 2, 6 and 10°C represent the mean sea water temperature, the 4°C increase in mean temperature by 2100 as predicted by IPCC scenario RCP8.5 (2013) and the extreme sea water temperature...

Parasitic outbreak of the copepod Balaenophilus manatorum in neonate loggerhead sea turtles (Caretta caretta) from a head-starting program.

Science.gov (United States)

Crespo-Picazo, J L; García-Parraga, D; Domènech, F; Tomás, J; Aznar, F J; Ortega, J; Corpa, J M

2017-06-02

Diseases associated to external parasitosis are scarcely reported in sea turtles. During the last decades several organism have been documented as a part of normal epibiont community connected to sea turtles. The copepod Balaenophilus manatorum has been cited as a part of epibiont fauna with some concern about its parasitic capacity. This study serves three purposes, i.e. (i) it sheds light on the type of life style that B. manatorum has developed with its hosts, particularly turtles; (ii) it makes a cautionary note of the potential health risks associated with B. manatorum in sea turtles under captivity conditions and in the wild, and (iii) it provides data on effective treatments against B. manatorum. We report for the first time a massive infestation of the copepod B. manatorum and subsequent acute mortality in a group of loggerhead sea turtle hatchlings. Four-month-old turtles from a head-starting program started exhibiting excitatory and fin rubbing behavior preceding an acute onset of lethargy, skin ulceration and death in some animals. All the individuals (n = 57) were affected by severe copepod load and presented different degrees of external macroscopic skin lesions. The ventral area of front flippers, axillar and pericloacal skin were mostly affected, and were the main parasite distribution regions. Copepods were also detected on plastron and carapace sutures. The gut contents of B. manatorum reacted positively for cytokeratin, indicating consumption of turtle skin. Severe ulcerative necrotic dermatitis and large amount of bacteria presence were the major histopathological findings. Individual fresh water immersion for 10 min and lufenuron administration (0.1 ppm) to the water system every 2 weeks proved effective for removing turtle parasites and to control re-infestation, respectively. The results from our study clearly indicated that B. manatorum individuals consume turtle skin. The pathological effects of this agent and the potential implications

UTILITY OF A FULL LIFE-CYCLE COPEPOD BIOASSAY APPROACH FOR ASSESSMENT OF SEDIMENT-ASSOCIATED CONTAMINANT MIXTURES. (R825279)

Science.gov (United States)

AbstractWe compared a 21 day full life-cycle bioassay with an existing 14 day partial life-cycle bioassay for two species of meiobenthic copepods, Microarthridion littorale and Amphiascus tenuiremis. We hypothesized that full life-cycle tests would bette...

Biosynthesis of coelenterazine in the deep-sea copepod, Metridia pacifica

Energy Technology Data Exchange (ETDEWEB)

Oba, Yuichi; Kato, Shin-ichi; Ojika, Makoto [Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-860 (Japan); Inouye, Satoshi, E-mail: sinouye@chisso.co.jp [Yokohama Research Center, Chisso Co., 5-1 Okawa, Kanazawa-ku, Yokohama 236-8605 (Japan)

2009-12-18

Coelenterazine is an imidazopyrazinone compound (3,7-dihydroimidazopyrazin-3-one structure) that is widely distributed in marine organisms and used as a luciferin for various bioluminescence reactions. We have used electrospray ionization-ion trap-mass spectrometry to investigate whether the deep-sea luminous copepod Metridia pacifica is able to synthesize coelenterazine. By feeding experiments using deuterium labeled amino acids of L-tyrosine and L-phenylalanine, we have shown that coelenterazine can be synthesized from two molecules of L-tyrosine and one molecule of L-phenylalanine in M. pacifica. This is the first demonstration that coelenterazine is biosynthesized from free L-amino acids in a marine organism.

Biosynthesis of coelenterazine in the deep-sea copepod, Metridia pacifica

International Nuclear Information System (INIS)

Oba, Yuichi; Kato, Shin-ichi; Ojika, Makoto; Inouye, Satoshi

2009-01-01

Coelenterazine is an imidazopyrazinone compound (3,7-dihydroimidazopyrazin-3-one structure) that is widely distributed in marine organisms and used as a luciferin for various bioluminescence reactions. We have used electrospray ionization-ion trap-mass spectrometry to investigate whether the deep-sea luminous copepod Metridia pacifica is able to synthesize coelenterazine. By feeding experiments using deuterium labeled amino acids of L-tyrosine and L-phenylalanine, we have shown that coelenterazine can be synthesized from two molecules of L-tyrosine and one molecule of L-phenylalanine in M. pacifica. This is the first demonstration that coelenterazine is biosynthesized from free L-amino acids in a marine organism.

Fatty acids in six small pelagic fish species and their crustacean prey from the mindanao sea, southern Philippines.

Science.gov (United States)

Metillo, Ephrime Bicoy; Aspiras-Eya, Anna Arlene

2014-08-01

Fatty acids are important in human health and useful in the analysis of the marine food web, however information on tropical pelagic organisms is scarce. Six zooplanktivorous small pelagic fish species (Decapterus kurroides, Decapterus macarellus, Selar crumenophthalmus, Sardinella lemuru, Spratilloides gracilis and Stolephorus insularis) and four of their zooplanktonic crustacean prey [three sergestoid species (Acetes erythraeus, Acetes intermedius and Lucifer penicillifer) and one calanoid copepod (Acartia erythraea)] were collected from the Mindanao Sea, and their fatty acids were profiled. The resulting profiles revealed 17 fatty acids that were specific to certain species and 9 {myristic acid [C14:0], palmitic acid [C16:0], stearic acid [C18:0]; palmitoleic acid [C16:1], oleic acid [C18:1n9c], linoleic acid [C18:2n6c], linolenic acid [C18:3n3], eicosapentaenoic acid (EPA) [C20:5n3] and docosahexaenoic acid (DHA) [C22:6n3]} that were common to all species. Cluster analysis and non-metric multidimensional scaling (NMDS) of fatty acids indicate a high similarity in profiles in all species, but separate fish and zooplankton clusters were obtained. Mackerel species (D. macarellus, D. kurroides and S. crumenophthalmus) had concentrations of total n-3 fatty acids that match those of their Acetes prey. The copepod A. erythraea and the sergestoid L. penicillifer exhibited the lowest values of the EPA:DHA ratio, which was most likely due to their phytoplanktivorous feeding habits, but the occurrence of the highest values of the ratio in Acetes suggests the inclusion of plant detritus in their diet. DHA values appear to affirm the trophic link among copepod, Lucifer, Acetes and mackerel species.

Effect of food type and concentration on growth and fatty acid composition of early larvae of the anchovy (Engraulis encrasicolus) reared under laboratory conditions

KAUST Repository

Garrido, Susana

2012-12-01

Experiments were conducted during the summer of 2008 and 2009 to study the growth of early post yolk-sac European anchovy (Engraulis encrasicolus, Linnaeus, 1758) larvae reared under different food regimes. The fatty acid composition was used to assess nutritional condition of the larvae. Prey items used in the experiments were Gymnodinium sanguineum, Brachionus plicatilis and nauplii of the copepods Acartia grani and Euterpina acutifrons. Food type and concentration affected the growth of the larvae. Mixed diets composed of rotifers and copepod nauplii at high concentration resulted in higher anchovy larvae growth rates in comparison with single-prey diets using either rotifers or copepod nauplii. The addition of the dinoflagellate G. sanguineum (25-50cellsml -1) to the prey offered did not enhance significantly larval growth. Highest growth rates of anchovy larvae (0.28mmd -1) were obtained using high concentrations of a mixed diet, particularly the combination of rotifers and A. grani nauplii. Fatty acid composition at hatch was similar to the composition observed in the field, but during larvae ontogeny there was a marked decrease in the contribution of polyunsaturated fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Such difference reflects the high requirements of these PUFA for larvae development, and suggests that the food offered failed to fulfill the larvae nutritional requirements. The growth rates obtained in our experiments were, overall, in the lower range of those observed in natural conditions. Taking into considerations the fact that larvae in the field are expected to encounter lower prey concentrations, we discuss the reasons for such disagreement. © 2012 Elsevier B.V.

Effect of food type and concentration on growth and fatty acid composition of early larvae of the anchovy (Engraulis encrasicolus) reared under laboratory conditions

KAUST Repository

Garrido, Susana; Saiz, Enric; Peters, Janna L.; Ré , Pedrobarcia; Á lvarez, Paula; Cotano, Unai; Herrero, D. L.; de Murguí a, Amalia Martí nez; Irigoien, Xabier

2012-01-01

Experiments were conducted during the summer of 2008 and 2009 to study the growth of early post yolk-sac European anchovy (Engraulis encrasicolus, Linnaeus, 1758) larvae reared under different food regimes. The fatty acid composition was used to assess nutritional condition of the larvae. Prey items used in the experiments were Gymnodinium sanguineum, Brachionus plicatilis and nauplii of the copepods Acartia grani and Euterpina acutifrons. Food type and concentration affected the growth of the larvae. Mixed diets composed of rotifers and copepod nauplii at high concentration resulted in higher anchovy larvae growth rates in comparison with single-prey diets using either rotifers or copepod nauplii. The addition of the dinoflagellate G. sanguineum (25-50cellsml -1) to the prey offered did not enhance significantly larval growth. Highest growth rates of anchovy larvae (0.28mmd -1) were obtained using high concentrations of a mixed diet, particularly the combination of rotifers and A. grani nauplii. Fatty acid composition at hatch was similar to the composition observed in the field, but during larvae ontogeny there was a marked decrease in the contribution of polyunsaturated fatty acids such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Such difference reflects the high requirements of these PUFA for larvae development, and suggests that the food offered failed to fulfill the larvae nutritional requirements. The growth rates obtained in our experiments were, overall, in the lower range of those observed in natural conditions. Taking into considerations the fact that larvae in the field are expected to encounter lower prey concentrations, we discuss the reasons for such disagreement. © 2012 Elsevier B.V.

Life-stage-specific differences in exploitation of food mixtures: diet mixing enhances copepod egg production but not juvenile development

DEFF Research Database (Denmark)

Koski, Marja; Breteler, W.K.; Schogt, N.

2006-01-01

, the copepods failed to moult past the first copepodite stage, and the mortality was high. In sharp contrast, mixing two nutritionally poor food species often resulted in egg production which was not significantly different from nutritionally high quality food, although hatching success in many mixtures was low......Development, egg production and hatching success of the calanoid copepods Temora longicornis and Pseudocalanus elongatus were measured in food mixtures to test their ability to obtain a complete nutrition by combining different nutritionally poor food species. In all the food mixtures used....... Whereas egg production was significantly correlated with particulate organic nitrogen in the diet, and independent of the highly unsaturated fatty acids (HUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), hatching increased with increasing DHA and EPA concentration. Growth and juvenile...

Benthic harpacticoid copepods of Jiaozhou Bay, Qingdao

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Ma, Lin; Li, Xinzheng

2017-09-01

The species richness of benthic harpacticoid copepod fauna in Jiaozhou Bay, Qingdao, on the southern coast of Shandong Peninsula, has not been comprehensively studied. We present a preliminary inventory of species for this region based on material found in nine sediment samples collected from 2011 to 2012. Our list includes 15 species belonging to 15 genera in 9 families, the most speciose family was the Miraciidae Dana, 1846 (seven species); all other families were represented by single species only. Sediment characteristics and depth are determined to be important environmental determinants of harpacticoid distribution in this region. We briefly detail the known distributions of species and provide a key to facilitate their identification. Both harpacticoid species richness and the species/genus ratio in Jiaozhou Bay are lower than in Bohai Gulf and Gwangyang Bay. The poor knowledge of the distribution of benthic harpacticoids, in addition to low sampling effort in Jiaozhou Bay, likely contribute to low species richness.

Distinctive mitochondrial genome of Calanoid copepod Calanus sinicus with multiple large non-coding regions and reshuffled gene order: Useful molecular markers for phylogenetic and population studies

Science.gov (United States)

2011-01-01

Background Copepods are highly diverse and abundant, resulting in extensive ecological radiation in marine ecosystems. Calanus sinicus dominates continental shelf waters in the northwest Pacific Ocean and plays an important role in the local ecosystem by linking primary production to higher trophic levels. A lack of effective molecular markers has hindered phylogenetic and population genetic studies concerning copepods. As they are genome-level informative, mitochondrial DNA sequences can be used as markers for population genetic studies and phylogenetic studies. Results The mitochondrial genome of C. sinicus is distinct from other arthropods owing to the concurrence of multiple non-coding regions and a reshuffled gene arrangement. Further particularities in the mitogenome of C. sinicus include low A + T-content, symmetrical nucleotide composition between strands, abbreviated stop codons for several PCGs and extended lengths of the genes atp6 and atp8 relative to other copepods. The monophyletic Copepoda should be placed within the Vericrustacea. The close affinity between Cyclopoida and Poecilostomatoida suggests reassigning the latter as subordinate to the former. Monophyly of Maxillopoda is rejected. Within the alignment of 11 C. sinicus mitogenomes, there are 397 variable sites harbouring three 'hotspot' variable sites and three microsatellite loci. Conclusion The occurrence of the circular subgenomic fragment during laboratory assays suggests that special caution should be taken when sequencing mitogenomes using long PCR. Such a phenomenon may provide additional evidence of mitochondrial DNA recombination, which appears to have been a prerequisite for shaping the present mitochondrial profile of C. sinicus during its evolution. The lack of synapomorphic gene arrangements among copepods has cast doubt on the utility of gene order as a useful molecular marker for deep phylogenetic analysis. However, mitochondrial genomic sequences have been valuable markers for

Optimal swimming strategies in mate searching pelagic copepods

DEFF Research Database (Denmark)

Kiørboe, Thomas

2008-01-01

Male copepods must swim to find females, but swimming increases the risk of meeting predators and is expensive in terms of energy expenditure. Here I address the trade-offs between gains and risks and the question of how much and how fast to swim using simple models that optimise the number...... of lifetime mate encounters. Radically different swimming strategies are predicted for different feeding behaviours, and these predictions are tested experimentally using representative species. In general, male swimming speeds and the difference in swimming speeds between the genders are predicted...... and observed to increase with increasing conflict between mate searching and feeding. It is high in ambush feeders, where searching (swimming) and feeding are mutually exclusive and low in species, where the matured males do not feed at all. Ambush feeding males alternate between stationary ambush feeding...

Egg production, growth and development of the cyclopoid copepod Oithona similis

DEFF Research Database (Denmark)

Sabatini, Marina; Kiørboe, Thomas

1994-01-01

Egg production, growth and development rates of Oithona similis were measured in the laboratory as a function of food concentration and composition. On an optimum diet, development is isochronal and growth is near exponential. The maximum juvenile growth rate at 15 degree C (0.2 day-1) is similar...... to juvenile growth in calanoid copepods. The maximum weight-specific egg production rate (0.1 day-1), on the other hand, is substantially less than in free-spawning calanoids, but similar to that in egg-carrying calanoids. In the Kattegat, Oithona spp. egg production is strongly limited by food during summer...

Overlooked cryptic endemism in copepods: systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida, Diaptomidae).

Science.gov (United States)

Marrone, Federico; Lo Brutto, Sabrina; Hundsdoerfer, Anna K; Arculeo, Marco

2013-01-01

Our comprehension of the phylogeny and diversity of most inland-water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the "Cosmopolitanism Paradigm" of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group. Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diaptomid subgenus Occidodiaptomus were investigated with the aim of comparing the patterns of morphological and molecular evolution in freshwater copepods. Three species currently lumped under the binomen Hemidiaptomus (Occidodiaptomus) ingens and two highly divergent clades within H. (O.) roubaui were distinguished, thus showing an apparent discordance between the molecular distances recorded and Occidodiaptomus morphological homogeneity, and highlighting a noteworthy decoupling between the morphological and molecular diversity in the subgenus. Current Occidodiaptomus diversity pattern is ascribed to a combined effect of ancient vicariance and recent dispersal events. It is stressed that the lack of sound calibration points for the molecular clock makes it difficult to soundly temporally frame the diversification events of interest in the taxon studied, and thus to asses the role of morphological bradytely and of accelerated molecular evolutionary rates in shaping the current diversity of the group. Copyright © 2012 Elsevier Inc. All rights reserved.

Characterization of the current biological communities within the Nanticoke River in the vicinity of the Vienna SES

International Nuclear Information System (INIS)

Stroup, C.F.; Brindley, A.; Kazyak, P.F.

1991-07-01

Pursuant to a utility's intent to file for permission to build a generating station along the Nanticoke River, Maryland, a field program was conducted to update characterizations of major aquatic biota of the river in proximity to the existing power plant and a potential intake/discharge location. This characterization sampled five stations on the Nanticoke River, spanning 14 miles from Chapter Point to Riverton, between July 1988 and October 1989. During the study period, the juvenile and adult fish community was dominated by white perch, Atlantic menhaden, bay anchovy, hogchoker, and spot. Spring ichthyoplankton was composed of white perch, striped bass, yellow perch, and alosids, while summer ichthyoplankton was dominated by naked gobies and bay anchovy. Acartia tonsa, Eurytemora affinis and Bosmina longirostris dominated zooplankton samples. The phytoplankton community was composed primarily of diatoms, green algae, and monads. Polychaetes and crustaceans were the dominant macrobenthic taxa, with molluscs contributing to total abundance primarily during spring recruitment. The final report presents the results of fish, ichthyoplankton, zooplankton, and benthic surveys conducted between July 1988 and October 1989 in the middle portion of the Nanticoke River, Maryland. During the dry conditions of 1988, aquatic communities were dominated by estuarine species, while the lower saline environment of 1989 resulted in the presence of more freshwater species

Tidal effects on short-term mesozooplankton distribution in small channels of a temperate-turbid estuary, Southwestern Atlantic

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Javier Chazarreta

2015-06-01

Full Text Available Abstract The short-term variability of mesozooplankton distribution and physicochemical variables was examined in two different channels of the Bahía Blanca Estuary, Argentina, during two tidal cycles. All the physicochemical measurements and mesozooplankton sampling were performed at a fixed site during approximately 22-23 h at 3-h intervals. Pumps were used to obtain surface and bottom mesozooplankton samples and the water speed of each stratum was measured with an Acoustic Doppler Current Profiler (ADCP. In all, 23 mesozooplanktonic taxa belonging to four phyla (Arthropoda, Annelida, Echinodermata and Chordata were identified. The most abundant taxa during the two tidal cycles were Balanus glandula larvae, Eurytemora americana and Acartia tonsa. A discernible variability in the water conditions and vertical mesozooplankton distribution (VMD different from that known for the estuary's main channel, was found in the other two selected channels. VMD varied during the tidal cycle in both channels in accordance with the channel's geomorphology and water dynamic characteristics of each of them. The variation of the abundance of the different taxa during ebb and flood currents might indicate the existence of a tidal vertical migration of the mesozooplankton as a response to particular dynamic water conditions.

Rare parasitic copepods (Siphonostomatoida: Lernanthropidae) from Egyptian Red Sea fishes.

Science.gov (United States)

El-Rashidy, Hoda Hassan; Boxshall, Geoffrey Allan

2016-10-01

Two rare species of parasitic copepods belonging to the genus Lernanthropus de Blainville, 1822 (Siphonostomatoida: Lernanthropidae) are redescribed in detail, based on material collected from Red Sea fishes, caught at El-Tor, near Sharm El-Sheikh on the Red Sea coast of Egypt. Adult females of Lernanthropus sanguineus Song & Chen, 1976 were found on the gills of snapper Lutjanus fulviflamma (Forsskål). This species was known only from its original description based on material from Chinese waters. Adult females of Lernanthropus triangularis Pillai, 1963 were obtained from the gills of mojarra Gerres oyena (Forsskål). Both parasite species are new records for Egyptian Red Sea waters and both host records are new.

Feeding season duration and the relative success of capital and income spawning copepods

DEFF Research Database (Denmark)

Sainmont, Julie; Varpe, Øystein; Andersen, Ken Haste

to the spring bloom, using only its reserves accumulated the previous year (capital breeder). The success of these two strategies is related to the length of the spring bloom, the only source of nutrients for these copepods. We use an individual based model to approach the question of income versus capital...... breeders in a highly seasonal environment, and find that the capital breeders have a higher fitness during short spring bloom while the income breeder has an improved performance over long productive seasons...

Strategies for success: Copepods in a seasonal world

DEFF Research Database (Denmark)

Sainmont, Julie

depth and plastic behaviors such as switching between feeding modes and daily vertical migration allowing them to quickly adapt to local conditions. Some of their life history traits also vary widely amongst species, including how resources are allocated to reproduction and size at maturity. This thesis...... night cycle as the eciency of visual predators varies with ambient light. An ecient strategy is thus to migrate vertically, feeding at the surface at night, and taking refuge at depth during the day. The rst part of this thesis treats DVM with some observations and models. A rst study, made from a video...... plankton recorder in the West coast of Greenland, shows the wide range of migration patterns adopted in the zooplankton community but also within the Calanus copepods taxa (chapter 2). A second study shows the emergence of the DVM strategy in a game theory approach, not only of the organism, but also...

A new species of the rare endoparasitic copepod Entobius (Copepoda: Entobiidae) from Mexico with a key to the species of the genus.

Science.gov (United States)

Suárez-Morales, Eduardo; Carrera-Parra, Luis F

2012-09-01

Abstract: In a study of the benthic polychaete fauna of the southern Gulf of Mexico and the Caribbean Sea, several specimens of the terebellid polychaete Scionides reticulata (Ehlers) were found to host endoparasitic copepods that represent an undescribed species of the rare cyclopoid genus Entobius Dogiel, 1948. The new species, E. scionides sp. n., can be distinguished from its congeners by a combination of characters including a genital region without constrictions, three-segmented antennules, a reduced antenna with a blunt terminal process, reduced ornamentation of endopods of legs 1-4 and its relatively small size (2.3-2.7 mm). It is the smallest species of the genus. Comments on immature females are also provided, but males of this species remain unknown. It has a high prevalence (53%) in populations of the terebellid S. reticulata in the southern Gulf of Mexico, but it is absent from the Caribbean. This is the first occurrence of this copepod genus in the Americas. The finding of the new species of Entobius in S. reticulata confirms the strict specificity of most members of the genus and expands the host range of this copepod genus. A key for the identification of the species of Entobius is provided.

Ammonium excretion and oxygen respiration of tropical copepods and euphausiids exposed to oxygen minimum zone conditions

Science.gov (United States)

Kiko, Rainer; Hauss, Helena; Buchholz, Friedrich; Melzner, Frank

2016-04-01

Calanoid copepods and euphausiids are key components of marine zooplankton communities worldwide. Most euphausiids and several copepod species perform diel vertical migrations (DVMs) that contribute to the export of particulate and dissolved matter to midwater depths. In vast areas of the global ocean, and in particular in the eastern tropical Atlantic and Pacific, the daytime distribution depth of many migrating organisms corresponds to the core of the oxygen minimum zone (OMZ). At depth, the animals experience reduced temperature and oxygen partial pressure (pO2) and an increased carbon dioxide partial pressure (pCO2) compared to their near-surface nighttime habitat. Although it is well known that low oxygen levels can inhibit respiratory activity, the respiration response of tropical copepods and euphausiids to relevant pCO2, pO2, and temperature conditions remains poorly parameterized. Further, the regulation of ammonium excretion at OMZ conditions is generally not well understood. It was recently estimated that DVM-mediated ammonium supply could fuel bacterial anaerobic ammonium oxidation - a major loss process for fixed nitrogen in the ocean considerably. These estimates were based on the implicit assumption that hypoxia or anoxia in combination with hypercapnia (elevated pCO2) does not result in a down-regulation of ammonium excretion. We exposed calanoid copepods from the Eastern Tropical North Atlantic (ETNA; Undinula vulgaris and Pleuromamma abdominalis) and euphausiids from the Eastern Tropical South Pacific (ETSP; Euphausia mucronata) and the ETNA (Euphausia gibboides) to different temperatures, carbon dioxide and oxygen levels to study their survival, respiration and excretion rates at these conditions. An increase in temperature by 10 °C led to an approximately 2-fold increase of the respiration and excretion rates of U. vulgaris (Q10, respiration = 1.4; Q10, NH4-excretion = 1.6), P. abdominalis (Q10, respiration = 2.0; Q10, NH4-excretion = 2.4) and

Ultraviolet B radiation induces impaired lifecycle traits and modulates expression of cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus

Energy Technology Data Exchange (ETDEWEB)

Puthumana, Jayesh; Lee, Min-Chul; Park, Jun Chul; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon, E-mail: jeonghoon@skku.edu; Lee, Jae-Seong, E-mail: jslee2@skku.edu

2017-03-15

Highlights: • Impaired effects of UV-B on the copepod Tigriopus japonicus were examined. • Modulation of entire CYP genes were analyzed in response to UV-B. • CYP inhibitor (PBO) confirmed the role of CYP in UV-B induced mortality. • Low-dose UV-B found induce developmental delays, and higher doses cause reproductive impairments. • Study predicted the mechanistic effects of UV-B in copepods through the AhR-mediated up-regulation of CYP genes. - Abstract: To evaluate the effects of ultraviolet B (UV-B) radiation at the developmental, reproductive, and molecular levels in aquatic invertebrates, we measured UV-B-induced acute toxicity, impairments in developmental and reproductive traits, and UV-B interaction with the entire family of cytochrome P450 (CYP) genes in the intertidal benthic copepod Tigriopus japonicus. We found a significant, dose-dependent reduction (P < 0.05) in the survival of T. japonicus that began as a developmental delay and decreased fecundity. The 48 h LD10 and LD50 were 1.35 and 1.84 kJ/m{sup 2}, and the CYP inhibitor (PBO) elevated mortality, confirming the involvement of CYP genes in UV-B induced toxicity. Low-dose UV-B (1.5 kJ/m{sup 2}) induced developmental delays, and higher doses (6–18 kJ/m{sup 2}) caused reproductive impairments in ovigerous females. The significant up-regulation of CYP genes belonging to clans 2/3/MT/4/20 in T. japonicus exposed to UV-B (12 kJ/m{sup 2}) confirmed molecular interaction between UV-B and CYP genes. Moreover, orphan CYPs, such as CYP20A1, provide good insight on the deorphanization of invertebrate CYPs. Overall, these results demonstrate the involvement of UV-B radiation in the expression of all the CYP genes in T. japonicus and their susceptibility to UV-B radiation. This will provide a better understanding of the mechanistic effects of UV-B in copepods through the predicted AhR-mediated up-regulation of CYP genes.

Ultraviolet B radiation induces impaired lifecycle traits and modulates expression of cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus

International Nuclear Information System (INIS)

Puthumana, Jayesh; Lee, Min-Chul; Park, Jun Chul; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon; Lee, Jae-Seong

2017-01-01

Highlights: • Impaired effects of UV-B on the copepod Tigriopus japonicus were examined. • Modulation of entire CYP genes were analyzed in response to UV-B. • CYP inhibitor (PBO) confirmed the role of CYP in UV-B induced mortality. • Low-dose UV-B found induce developmental delays, and higher doses cause reproductive impairments. • Study predicted the mechanistic effects of UV-B in copepods through the AhR-mediated up-regulation of CYP genes. - Abstract: To evaluate the effects of ultraviolet B (UV-B) radiation at the developmental, reproductive, and molecular levels in aquatic invertebrates, we measured UV-B-induced acute toxicity, impairments in developmental and reproductive traits, and UV-B interaction with the entire family of cytochrome P450 (CYP) genes in the intertidal benthic copepod Tigriopus japonicus. We found a significant, dose-dependent reduction (P < 0.05) in the survival of T. japonicus that began as a developmental delay and decreased fecundity. The 48 h LD10 and LD50 were 1.35 and 1.84 kJ/m"2, and the CYP inhibitor (PBO) elevated mortality, confirming the involvement of CYP genes in UV-B induced toxicity. Low-dose UV-B (1.5 kJ/m"2) induced developmental delays, and higher doses (6–18 kJ/m"2) caused reproductive impairments in ovigerous females. The significant up-regulation of CYP genes belonging to clans 2/3/MT/4/20 in T. japonicus exposed to UV-B (12 kJ/m"2) confirmed molecular interaction between UV-B and CYP genes. Moreover, orphan CYPs, such as CYP20A1, provide good insight on the deorphanization of invertebrate CYPs. Overall, these results demonstrate the involvement of UV-B radiation in the expression of all the CYP genes in T. japonicus and their susceptibility to UV-B radiation. This will provide a better understanding of the mechanistic effects of UV-B in copepods through the predicted AhR-mediated up-regulation of CYP genes.

The fate of copepod populations in the Paranapanema River (São Paulo, Brazil, downstream from the Jurumirim dam

Directory of Open Access Journals (Sweden)

Mitsuka Patricia Maria

2002-01-01

Full Text Available The longitudinal changes in the structure of copepod populations were examined during the dry and rainy seasons in a 42 km stretch of the Paranapanema River downstream from the dam of the Jurumirim Reservoir. Samples were taken in the "lacustrine" zone of the reservoir near the dam, and also at 12 stations distributed in the middle and the lateral regions of the channel of the Paranapanema River downstream from the dam. The following species of Cyclopoida were found at the sites: Thermocyclops decipiens, Thermocyclops minutus, Paracyclops sp., Tropocyclops sp and Mesocyclops sp., and of Calanoida: Argyrodiaptomus furcatus, Notodiaptomus iheringi and Notodiaptomus conifer. In the reservoir sampling station, the copepod abundance during the dry and rainy seasons corresponded to 41 and 51% of the total zooplankton, respectively. This difference could be related to the rainfall and water level variations, and especially to the influence of variables such as water temperature, dissolved oxygen and chlorophyll-a contents. No significant differences in organism numbers were recorded among samples of zooplankton taken in the middle and near-bank parts of the river. In relation to longitudinal variation in the Paranapanema River stretch, a significant decrease in density and disappearance of some species were recorded 11km downstream of the dam during the dry season. At the stations 32km from the dam, a drastic reduction in copepod abundance was observed in the rainy season. These observations could be linked not only to environmental changes from lentic to lotic conditions, but also to the combination of certain factors such as current velocity, water outflow of the reservoir, and rainfall.

UV-B radiation-induced oxidative stress and p38 signaling pathway involvement in the benthic copepod Tigriopus japonicus.

Science.gov (United States)

Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Kyun-Woo; Kim, Min-Jung; Shin, Kyung-Hoon; Lee, Su-Jae; Lee, Young-Mi; Lee, Jae-Seong

2015-01-01

Ultraviolet B (UV-B) radiation presents an environmental hazard to aquatic organisms. To understand the molecular responses of the intertidal copepod Tigriopus japonicus to UV-B radiation, we measured the acute toxicity response to 96 h of UV-B radiation, and we also assessed the intracellular reactive oxygen species (ROS) levels, glutathione (GSH) content, and antioxidant enzyme (GST, GR, GPx, and SOD) activities after 24 h of exposure to UV-B with LD50 and half LD50 values. Also, expression patterns of p53 and hsp gene families with phosphorylation of p38 MAPK were investigated in UV-B-exposed copepods. We found that the ROS level, GSH content, and antioxidant enzyme activity levels were increased with the transcriptional upregulation of antioxidant-related genes, indicating that UV-B induces oxidative stress by generating ROS and stimulating antioxidant enzymatic activity as a defense mechanism. Additionally, we found that p53 expression was significantly increased after UV-B irradiation due to increases in the phosphorylation of the stress-responsive p38 MAPK, indicating that UV-B may be responsible for inducing DNA damage in T. japonicus. Of the hsp family genes, transcriptional levels of hsp20, hsp20.7, hsp70, and hsp90 were elevated in response to a low dose of UV-B radiation (9 kJ m(-2)), suggesting that these hsp genes may be involved in cellular protection against UV-B radiation. In this paper, we performed a pathway-oriented mechanistic analysis in response to UV-B radiation, and this analysis provides a better understanding of the effects of UV-B in the intertidal benthic copepod T. japonicus. Copyright © 2014 Elsevier Inc. All rights reserved.

Laboratory and field efficacy of Pedalium murex and predatory copepod, Mesocyclops longisetus on rural malaria vector, Anopheles culicifacies

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Thangadurai Chitra

2013-04-01

Full Text Available Objective: To test the potentiality of the leaf extract of Pedalium murex (P. murex and predatory copepod Mesocyclops longisetus (M. longisetus in individual and combination in controlling the rural malarial vector, Anopheles culicifacies (An. culicifacies in laboratory and field studies. Methods: P. murex leaves were collected from in and around Erode, Tamilnadu, India. The active compounds were extracted with 300 mL of methanol for 8 h in a Soxhlet apparatus. Laboratory studies on larvicidal and pupicidal effects of methanolic extract of P. murex tested against the rural malarial vector, An. culicifacies were significant. Results: Evaluated lethal concentrations (LC50 of P. murex extract were 2.68, 3.60, 4.50, 6.44 and 7.60 mg/L for I, II, III, IV and pupae of An. culicifacies, respectively. Predatory copepod, M. longisetus was examined for their predatory efficacy against the malarial vector, An. culicifacies. M. longisetus showed effective predation on the early instar (47% and 36% on I and II instar when compared with the later ones (3% and 1% on III and IV instar. Predatory efficacy of M. longisetus was increased (70% and 45% on I and II instar when the application was along with the P. murex extract. Conclusions: Predator survival test showed that the methanolic extract of P. murex is non-toxic to the predatory copepod, M. longisetus. Experiments were also conducted to evaluate the efficacy of methanolic extract of P. murex and M. longisetus in the direct breeding sites (paddy fields of An. culicifacies. Reduction in larval density was very high and sustained for a long time in combined treatment of P. murex and M. longisetus.

Alternative Methods for Marine Harpacticoid Copepod, Macrosetella gracilis Production in Marine Fish Larviculture

OpenAIRE

N. Jeyaraj; P. Santhanam; P. Raju; S. Ananth; K. Jothiraj

2014-01-01

Sustainable aquaculture depends upon eco-friendly, economically and socially viable culture systems. The recycling of organic wastes for plankton culture serves the dual purpose of cleaning the environment and providing economic benefits. There has been no experimentation to measure the effect of organic manure for the aquaculture of copepods, it may be reduced time and labor cost. Hence, the present experiment was conducted to evaluate the mass culture feasibili...

The copepod Tigriopus: A promising marine model organism for ecotoxicology and environmental genomics

Energy Technology Data Exchange (ETDEWEB)

Raisuddin, Sheikh [Department of Chemistry and the National Research Lab of Marine Molecular and Environmental Bioscience, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kwok, Kevin W.H. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China); Leung, Kenneth M.Y. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China); Schlenk, Daniel [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States); Lee, Jae-Seong [Department of Chemistry and the National Research Lab of Marine Molecular and Environmental Bioscience, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)]. E-mail: jslee2@hanyang.ac.kr

2007-07-20

There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in such efforts. Tigriopus and other copepods are widely distributed and ecologically important organisms. Their position in marine food chains is very prominent, especially with regard to the transfer of energy. Copepods also play an important role in the transportation of aquatic pollutants across the food chains. In recent years there has been a phenomenal increase in the knowledge base of Tigriopus spp., particularly in the areas of their ecology, geophylogeny, genomics and their behavioural, biochemical and molecular responses following exposure to environmental stressors and chemicals. Sequences of a number of important marker genes have been studied in various Tigriopus spp., notably T. californicus and T. japonicus. These genes belong to normal biophysiological functions (e.g. electron transport system enzymes) as well as stress and toxic chemical exposure responses (heat shock protein 20, glutathione reductase, glutathione S-transferase). Recently, 40,740 expressed sequenced tags (ESTs) from T. japonicus, have been sequenced and of them, 5673 ESTs showed significant hits (E-value, >1.0E-05) to the red flour beetle Tribolium genome database. Metals and organic pollutants such as antifouling agents, pesticides, polycyclic aromatic hydrocarbons (PAH) and polychrlorinated biphenyls (PCB) have shown reproducible biological responses when tested in Tigriopus spp. Promising results have been obtained when Tigriopus was used for assessment of risk associated with exposure to endocrine-disrupting chemicals (EDCs). Application of environmental

The copepod Tigriopus: A promising marine model organism for ecotoxicology and environmental genomics

International Nuclear Information System (INIS)

Raisuddin, Sheikh; Kwok, Kevin W.H.; Leung, Kenneth M.Y.; Schlenk, Daniel; Lee, Jae-Seong

2007-01-01

There is an increasing body of evidence to support the significant role of invertebrates in assessing impacts of environmental contaminants on marine ecosystems. Therefore, in recent years massive efforts have been directed to identify viable and ecologically relevant invertebrate toxicity testing models. Tigriopus, a harpacticoid copepod has a number of promising characteristics which make it a candidate worth consideration in such efforts. Tigriopus and other copepods are widely distributed and ecologically important organisms. Their position in marine food chains is very prominent, especially with regard to the transfer of energy. Copepods also play an important role in the transportation of aquatic pollutants across the food chains. In recent years there has been a phenomenal increase in the knowledge base of Tigriopus spp., particularly in the areas of their ecology, geophylogeny, genomics and their behavioural, biochemical and molecular responses following exposure to environmental stressors and chemicals. Sequences of a number of important marker genes have been studied in various Tigriopus spp., notably T. californicus and T. japonicus. These genes belong to normal biophysiological functions (e.g. electron transport system enzymes) as well as stress and toxic chemical exposure responses (heat shock protein 20, glutathione reductase, glutathione S-transferase). Recently, 40,740 expressed sequenced tags (ESTs) from T. japonicus, have been sequenced and of them, 5673 ESTs showed significant hits (E-value, >1.0E-05) to the red flour beetle Tribolium genome database. Metals and organic pollutants such as antifouling agents, pesticides, polycyclic aromatic hydrocarbons (PAH) and polychrlorinated biphenyls (PCB) have shown reproducible biological responses when tested in Tigriopus spp. Promising results have been obtained when Tigriopus was used for assessment of risk associated with exposure to endocrine-disrupting chemicals (EDCs). Application of environmental

Cadmium incorporation by the marine copepod Pseudodiaptomus coronatus

International Nuclear Information System (INIS)

Sick, L.V.; Baptist, G.J.

1979-01-01

Pseudodiaptomus coronatus, after exposure to phytoplankton and cadmium in concentrations like those in temperate, coastal environments, incorporated 109 Cd at higher rates from ambient water than from phytoplankton food. When ambient stable cadmium concentrations were increased from 0.03 to 1.00 μg.liter -1 , cadmium concentration by phytoplankton cells increased and the rate of cell ingestion by P. coronatus decreased. This inverse relation between the accumulation of cadmium in phytoplankton cells and the animal's ingestion rate resulted in relatively small net increases in the cadmium accumulated from phytoplankton by copepods. Rates of stable cadmium ingestion for P. coronatus ranged from 0.18 to 0.38 ng.mg animal dry wt -1 .h -1 , depending on the initial algal cell density and the ambient cadmium concentration. For cadmium concentrations of 0.03 to 1.00 μg.liter -1 , percentage assimilation efficiencies ranged from 13.20 to 68.40. Both rates of cadmium ingestion and assimilation efficiencies were higher than published values for carnivorous zooplankton

Effect of diatom morphology on the small-scale behavior of the copepod Temora stylifera (Dana, 1849)

KAUST Repository

Mahadik, Gauri A.

2017-05-12

We explored the small-scale behavior of the calanoid copepod Temora stylifera in relation to the diatoms Chaetoceros socialis, Leptocylindrus aporus, Leptocylindrus danicus and Pseudo-nitzschia calliantha offered as monospecific diets at similar carbon concentrations. These four diatoms are characterized by distinct size, shape and colony forming ability and are important components of the autumnal bloom co-occurring with the seasonal peak of T. stylifera abundance in Mediterranean coastal waters. High-speed video recordings showed that T. stylifera acquired cells in a suspension feeding mode while creating feeding currents. Copepod behavior was quantified in terms of feeding, motion, and grooming activities. T. stylifera spent more time in hovering than cruising in presence of all diets. The solitary L. aporus and P. calliantha elicited longer feeding bouts, lower appendage beat frequency and shorter grooming events compared to the colonial L. danicus and C. socialis. Overall the present results indicate that the behavioral responses of T. stylifera to different diatom diets were species-specific. The observed behavioral plasticity may help T. stylifera to adjust rapidly to changes in the food environment and this can be advantageous in exploiting short-lived phytoplankton blooms.

Effect of diatom morphology on the small-scale behavior of the copepod Temora stylifera (Dana, 1849)

KAUST Repository

Mahadik, Gauri A.; Castellani, Claudia; Mazzocchi, Maria Grazia

2017-01-01

We explored the small-scale behavior of the calanoid copepod Temora stylifera in relation to the diatoms Chaetoceros socialis, Leptocylindrus aporus, Leptocylindrus danicus and Pseudo-nitzschia calliantha offered as monospecific diets at similar carbon concentrations. These four diatoms are characterized by distinct size, shape and colony forming ability and are important components of the autumnal bloom co-occurring with the seasonal peak of T. stylifera abundance in Mediterranean coastal waters. High-speed video recordings showed that T. stylifera acquired cells in a suspension feeding mode while creating feeding currents. Copepod behavior was quantified in terms of feeding, motion, and grooming activities. T. stylifera spent more time in hovering than cruising in presence of all diets. The solitary L. aporus and P. calliantha elicited longer feeding bouts, lower appendage beat frequency and shorter grooming events compared to the colonial L. danicus and C. socialis. Overall the present results indicate that the behavioral responses of T. stylifera to different diatom diets were species-specific. The observed behavioral plasticity may help T. stylifera to adjust rapidly to changes in the food environment and this can be advantageous in exploiting short-lived phytoplankton blooms.

Effects of three PBDEs on development, reproduction and population growth rate of the harpacticoid copepod Nitocra spinipes

DEFF Research Database (Denmark)

Breitholtz, M.; Wollenberger, Leah

2003-01-01

and -100 on larval development rate (LDR) and population growth rate (r(m)). LDR significantly decreased in copepods exposed for 6 days to nominal concentrations greater than or equal to 0.013 mg/l BDE-47 and greater than or equal to 0.03 mg/l BDE-99. Large concentration ratios ( less than or equal to 338...

Zooplankton variability and copepod assemblage in the coastal and estuarine waters of Goa along the central-west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Achuthankutty, C.T.; Ramaiah, Neelam; Padmavati, G.

period and several species move into the high saline coastal waters. On recovery of the salinity, they repopulate and flourish in the estuary. Copepods are generally grouped on salinity preference, and in this case 3 categories are recognized viz. wide (5...

Impacts of an uncontrolled phosphogypsum dumpsite on summer distribution of phytoplankton, copepods and ciliates in relation to abiotic variables along the near-shore of the southwestern Mediterranean coast

International Nuclear Information System (INIS)

Rekik, Amira; Drira, Zaher; Guermazi, Wassim; Elloumi, Jannet; Maalej, Sami; Aleya, Lotfi; Ayadi, Habib

2012-01-01

In connection with the Taparura Project, studies of spatial distribution of the crustacean zooplankton community, nutrients, phytoplankton and ciliates were conducted in July 2007 at 45 stations spread over fifteen transects along the coast north of Sfax. The results showed that the N/P ratio was lower than the Redfield ratio, suggesting potential N limitation. Phytoplankton was characterised by the proliferation of several diatoms, while ciliates were largely dominated by spirotrichs. Copepods were the most abundant zooplankton present during the entire study period, comprising 61% of the total zooplankton community. Twelve copepod families were identified at every station, with a high percentage of Oithonidae (77% of copepods) dominated by Oithona nana. The abundance of this species was correlated with that of diatoms, Cocoolithophorideae and ciliated Colpodea, suggesting that O. nana may feed on a wide range of prey. Despite human pressure and industrial activities, the coastal waters north of Sfax showed a wide diversity of phytoplankton, ciliates and zooplankton.

Transcriptional profiles of Rel/NF-κB, inhibitor of NF-κB (IκB), and lipopolysaccharide-induced TNF-α factor (LITAF) in the lipopolysaccharide (LPS) and two Vibrio sp.-exposed intertidal copepod, Tigriopus japonicus.

Science.gov (United States)

Kim, Bo-Mi; Jeong, Chang-Bum; Rhee, Jae-Sung; Lee, Jae-Seong

2014-02-01

The immune system and the role of immunity-related genes have rarely been studied in copepods, even though copepods have a primitive immune response system and also have a potential in pathogen transport higher trophic levels. In this study, we firstly cloned and characterized three core immune genes such as nuclear factor κB (NF-κB), inhibitor of NF-κB (IκB), and lipopolysaccharide-induced TNF-α factor (LITAF) genes in the intertidal copepod Tigriopus japonicus. Several in silico analyses based on conserved domains, motifs, and phylogenetic relationships were supporting their annotations. To investigate the immune-related role of three genes, we exposed lipopolysaccharide (LPS) and two Vibrio sp. to T. japonicus. After exposure of different concentrations of LPS and two Vibrio sp., transcripts of TJ-IκB and TJ-LITAF genes were significantly elevated during the time course in a dose-dependent manner, while TJ-NF-κB transcripts were not significantly changed during exposure. These findings demonstrated that the copepod T. japonicus has a conserved immunity against infection. Copyright © 2013 Elsevier Ltd. All rights reserved.

EFFECT OF SALINITY VARIATION AND PESTICIDE EXPOSURE ON AN ESTUARINE HARPACTICOID COPEPOD, MICROARTHRIDION LITTORALE (POPPE), IN THE SOUTHEASTERN US. (R827397)

Science.gov (United States)

The harpacticoid copepod Microarthridion littorale (Poppe) was tested for interaction effects between salinity change and acute pesticide exposure on the survival and genotypic composition of a South Carolina population. Previous data suggested a significant link betwee...

Copepod grazing and their impact on phytoplankton standing stock and production in a tropical coastal water during the different seasons

Digital Repository Service at National Institute of Oceanography (India)

Jagadeesan, L.; Jyothibabu, R.; Arunpandi, N.; Parthasarathi, S.

during the PRM (1354 No m^-3) and PSWM (1606 No m^-3) than during PKSWM and LSWM (4571 and 3432 No m^-3, respectively). Seasonal changes in phytoplankton biomass, phytoplankton size structure, and copepod community were...

Solid phase extraction and metabolic profiling of exudates from living copepods

DEFF Research Database (Denmark)

Selander, Erik; Heuschele, Jan; Nylund, Göran M.

2016-01-01

describe the development of a closed loop solid phase extraction setup that allows for extraction of exuded metabolites from live copepods. We captured exudates from male and female Temora longicornis and analyzed the content with high resolution LC-MS. Chemometric methods revealed 87 compounds...... that solid phase extraction in combination with metabolic profiling of exudates is a useful tool to develop our understanding of the chemical interplay between pelagic organisms....... Copepodamide G, known to induce defensive responses in phytoplankton, was among the ten compounds of highest relative abundance in both male and female extracts. The presence of copepodamide G shows that the method can be used to capture and analyze chemical signals from living source organisms. We conclude...

Seasonal changes in food quantity and quality of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus: a bioassay approach

DEFF Research Database (Denmark)

Koski, Marja; Dutz, Jörg; Klein Breteler, W.

2010-01-01

We evaluated the food quantity and quality over a seasonal cycle for the development and egg production of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus, using a bioassay approach. Seston was sampled from December to October from a well-mixed water column of the Mar......We evaluated the food quantity and quality over a seasonal cycle for the development and egg production of the common North Sea copepods Temora longicornis and Pseudocalanus elongatus, using a bioassay approach. Seston was sampled from December to October from a well-mixed water column...... with the seston from the spring bloom in March-April. The juveniles of both species were able to complete their development only in spring experiments. A multiple regression analyses and comparison to a good-quality standard food of the same concentration suggested that, in an annual scale, the egg production...

Toxicity of antifouling biocides to the intertidal harpacticoid copepod Tigriopus japonicus (Crustacea, Copepoda): Effects of temperature and salinity

International Nuclear Information System (INIS)

Kwok, K.W.H.; Leung, K.M.Y.

2005-01-01

Intertidal harpacticoid copepods are commonly used in eco-toxicity tests worldwide. They predominately live in mid-high shore rock pools and often experience a wide range of temperature and salinity fluctuation. Most eco-toxicity tests are conducted at fixed temperature and salinity and thus the influence of these environmental factors on chemical toxicity is largely unknown. This study investigated the combined effect of temperature and salinity on the acute toxicity of the copepod Tigriopus japonicus against two common biocides, copper (Cu) and tributyltin (TBT) using a 2 x 3 x 4 factorial design (i.e. two temperatures: 25 and 35 o C; three salinities: 15.0 per mille , 34.5 per mille and 45.0 per mille ; three levels of the biocide plus a control). Copper sulphate and tributyltin chloride were used as the test chemicals while distilled water and acetone were utilised as solvents for Cu and TBT respectively. 96h-LC50s of Cu and TBT were 1024 and 0.149 μg l -1 respectively (at 25 o C; 34.5 per mille ) and, based on these results, nominal biocide concentrations of LC0 (i.e. control), LC30, LC50 and LC70 were employed. Analysis of Covariance using 'concentration' as the covariate and both 'temperature' and 'salinity' as fixed factors, showed a significant interaction between temperature and salinity effects for Cu, mortality increasing with temperature but decreasing with elevated salinity. A similar result was revealed for TBT. Both temperature and salinity are, therefore, important factors affecting the results of acute eco-toxicity tests using these marine copepods. We recommend that such eco-toxicity tests should be conducted at a range of environmentally realistic temperature/salinity regimes, as this will enhance the sensitivity of the test and improve the safety margin in line with the precautionary principle

Toxicity of antifouling biocides to the intertidal harpacticoid copepod Tigriopus japonicus (Crustacea, Copepoda): Effects of temperature and salinity

Energy Technology Data Exchange (ETDEWEB)

Kwok, K.W.H. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China); Leung, K.M.Y. [Swire Institute of Marine Science, Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam, Hong Kong (China)]. E-mail: kmyleung@hkucc.hku.hk

2005-07-01

Intertidal harpacticoid copepods are commonly used in eco-toxicity tests worldwide. They predominately live in mid-high shore rock pools and often experience a wide range of temperature and salinity fluctuation. Most eco-toxicity tests are conducted at fixed temperature and salinity and thus the influence of these environmental factors on chemical toxicity is largely unknown. This study investigated the combined effect of temperature and salinity on the acute toxicity of the copepod Tigriopus japonicus against two common biocides, copper (Cu) and tributyltin (TBT) using a 2 x 3 x 4 factorial design (i.e. two temperatures: 25 and 35 {sup o}C; three salinities: 15.0 per mille , 34.5 per mille and 45.0 per mille ; three levels of the biocide plus a control). Copper sulphate and tributyltin chloride were used as the test chemicals while distilled water and acetone were utilised as solvents for Cu and TBT respectively. 96h-LC50s of Cu and TBT were 1024 and 0.149 {mu}g l{sup -1} respectively (at 25 {sup o}C; 34.5 per mille ) and, based on these results, nominal biocide concentrations of LC0 (i.e. control), LC30, LC50 and LC70 were employed. Analysis of Covariance using 'concentration' as the covariate and both 'temperature' and 'salinity' as fixed factors, showed a significant interaction between temperature and salinity effects for Cu, mortality increasing with temperature but decreasing with elevated salinity. A similar result was revealed for TBT. Both temperature and salinity are, therefore, important factors affecting the results of acute eco-toxicity tests using these marine copepods. We recommend that such eco-toxicity tests should be conducted at a range of environmentally realistic temperature/salinity regimes, as this will enhance the sensitivity of the test and improve the safety margin in line with the precautionary principle.

Adverse effects of MWCNTs on life parameters, antioxidant systems, and activation of MAPK signaling pathways in the copepod Paracyclopina nana.

Science.gov (United States)

Kim, Duck-Hyun; Puthumana, Jayesh; Kang, Hye-Min; Lee, Min-Chul; Jeong, Chang-Bum; Han, Jeonghoon; Hwang, Dae-Sik; Kim, Il-Chan; Lee, Jin Wuk; Lee, Jae-Seong

2016-10-01

Engineered multi-walled carbon nanotubes (MWCNTs) have received widespread applications in a broad variety of commercial products due to low production cost. Despite their significant commercial applications, CNTs are being discharged to aquatic ecosystem, leading a threat to aquatic life. Thus, we investigated the adverse effect of CNTs on the marine copepod Paracyclopina nana. Additional to the study on the uptake of CNTs and acute toxicity, adverse effects on life parameters (e.g. growth, fecundity, and size) were analyzed in response to various concentrations of CNTs. Also, as a measurement of cellular damage, oxidative stress-related markers were examined in a time-dependent manner. Moreover, activation of redox-sensitive mitogen-activated protein kinase (MAPK) signaling pathways along with the phosphorylation pattern of extracellular signal-regulated kinase (ERK), p38, and c-Jun-N-terminal kinases (JNK) were analyzed to obtain a better understanding of molecular mechanism of oxidative stress-induced toxicity in the copepod P. nana. As a result, significant inhibition on life parameters and evoked antioxidant systems were observed without ROS induction. In addition, CNTs activated MAPK signaling pathway via ERK, suggesting that phosphorylated ERK (p-ERK)-mediated adverse effects are the primary cause of in vitro and in vivo endpoints in response to CNTs exposure. Moreover, ROS-independent activation of MAPK signaling pathway was observed. These findings will provide a better understanding of the mode of action of CNTs on the copepod P. nana at cellular and molecular level and insight on possible ecotoxicological implications in the marine environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Different zooplankton structures in the German Bight

Science.gov (United States)

Martens, P.; Brockmann, U.

1993-06-01

In August 1982, a net of 48 stations with altogether 208 samples was investigated in the eastern German Bight with respect to temperature, salinity, as well as the amount and species composition of the mesozooplankton (>80 μm). The data were arranged into different structures by means of a cluster analysis. Four different clusters were found: (a) a “Wadden sea water” with few holoplankton organisms but a higher amount of spionid larvae; (b) a “German Bight water” with a maximum occurrence of turbellaria ( Alaurina composita) and medium concentrations of copepods; (c) a mixing area between these two water masses with highest amounts of Oikopleura dioica, Temora longicornis, Acartia sp., mussel larvae and larvae of the spionid worms; (d) a “North Sea water” mass with highest concentrations of Pseudocalanus elongatus, Paracalanus parvus und Oithona similis. The differences in the concentrations of the species mentioned between the four clusters were significant on the 0.1%-level.

Seasonal dynamics of the copepod community in a tropical monsoonal estuary and the role of sex ratio in their abundance pattern

Digital Repository Service at National Institute of Oceanography (India)

Vineetha, G.; Madhu, N.V.; Kusum, K.K.; Sooria, P.M.

structure of copepods in the tropical monsoonal estuarine system.The ecological scenario in the Cochin estuary revealed that irrespective of the season, higher zooplankton abundance occurred in the mesohaline zone (MSZ; salinity 5–18) of the estuary, despite...

Deterioration in the biodiversity of copepods in sewage laiden creeks of Mumbai coast, west coast of India: A statistical approach.

Digital Repository Service at National Institute of Oceanography (India)

Stephen, R.; Jayalakshmy, K.V.; Nair, V.R.; Gajbhiye, S.N.; Jacob, B.

by many typical marine forms . Minimum diversity is recorded in BSE in the upper reaches. During post monsoon period the percentage of copepods varied from 0.1% to 83.7% with an average of 43.7% and density of 2018/100m 3 . Highest percentage...

Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS.

Science.gov (United States)

Han, Jeonghoon; Won, Eun-Ji; Lee, Min-Chul; Seo, Jung Soo; Lee, Su-Jae; Lee, Jae-Seong

2015-08-01

2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and perfluorooctane sulfonate (PFOS) are widely dispersed persistent organic pollutants (POPs) in the marine ecosystem. However, their toxic effects on marine organisms are still poorly understood. In this study, we investigated the effects of BDE-47 and PFOS on development and reproduction at the organismal level and reactive oxygen species (ROS) production and gene expression patterns of the defensome at the cellular level in the intertidal copepod Tigriopus japonicus. In copepods exposed to BDE-47 and PFOS, we observed developmental retardation and reduced fecundity, suggesting repercussions on in vivo endpoints through alterations to the normal molting and reproduction system of T. japonicus. BDE-47 and PFOS increased levels of ROS in T. japonicus in a concentration-dependent manner, indicating that POPs can induce oxidative stress through the generation of ROS. Additionally, transcript profiles of genes related to detoxification (e.g., CYPs), antioxidant functions (e.g., GST- sigma, catalase, MnSOD), apoptosis (e.g., p53, Rb), and cellular proliferation (e.g., PCNA) were modulated over 72h in response to BDE-47 (120μg/L) and PFOS (1000μg/L). These findings indicate that BDE-47 and PFOS can induce oxidative stress-mediated DNA damage repair systems with transcriptional regulation of detoxification, antioxidant, and apoptosis-related genes, resulting in developmental retardation and reduced fecundity in the copepod T. japonicus. Copyright © 2015 Elsevier B.V. All rights reserved.

A brominated flame retardant 2,2',4,4' tetrabrominated diphenyl ether (BDE-47) leads to lipogenesis in the copepod Tigriopus japonicus.

Science.gov (United States)

Lee, Min-Chul; Han, Jeonghoon; Lee, Seung-Hwi; Kim, Duck-Hyun; Kang, Hye-Min; Won, Eun-Ji; Hwang, Dae-Sik; Park, Jun Chul; Om, Ae-Son; Lee, Jae-Seong

2016-09-01

De novo lipogenesis (DNL) is a fatty acid synthesis process that requires several genes, including sterol regulatory element binding protein (SREBP), ATP-citrate lyase (ACLY), and acetyl-CoA carboxylase (ACC). DNL up-regulation is able to induce fat accumulation through an increase in fatty acids. To investigate the relationship between DNL up-regulation and the accumulation of fatty acids and lipid droplets in response to 2,2',4,4' tetrabrominated diphenyl ether (BDE-47), we examined DNL in the copepod Tigriopus japonicus. Transcription levels of DNL-related genes were increased after exposure to 2.5μg/L BDE-47 for 24h. After exposure to 2.5μg/L BDE-47, palmitic acid was significantly increased (Pcopepod. This study provides a better understanding of the effects of BDE-47 on DNL in copepods. Copyright © 2016 Elsevier B.V. All rights reserved.

Heavy metals induce oxidative stress and trigger oxidative stress-mediated heat shock protein (hsp) modulation in the intertidal copepod Tigriopus japonicus.

Science.gov (United States)

Kim, Bo-Mi; Rhee, Jae-Sung; Jeong, Chang-Bum; Seo, Jung Soo; Park, Gyung Soo; Lee, Young-Mi; Lee, Jae-Seong

2014-11-01

Heat shock proteins (hsps) are induced by a wide range of environmental stressors including heavy metals in aquatic organisms. However, the effect of heavy metals on zooplankton at the molecular level remains still unclear. In this study, we measured the intracellular reactive oxygen species (ROS) level and the antioxidant enzyme activities for 96 h after exposure to five heavy metals: arsenic (As), cadmium (Cd), copper (Cu), silver (Ag), and zinc (Zn) in the intertidal copepod Tigriopus japonicus. Activities of the antioxidant enzymes were highly elevated in metal-exposed copepods, indicating that heavy metals can induce oxidative stress by generating ROS, and stimulate the involvement of antioxidant enzymes as cellular defense mechanisms. Subsequently, transcriptional changes in hsp gene families were further investigated in the metal-exposed groups for 96 h. The ROS level and glutathione (GSH) content were significantly increased in Ag-, As-, and Cu-exposed copepods, while they were only slightly elevated in Cd- and Zn-exposed groups. Based on the numbers of significantly modulated hsp genes and their expression levels for 96 h, we measured the effect of heavy metals to stress genes of T. japonicus in the following order: Cu > Zn > Ag > As > Cd, implying that Cu acts as a stronger oxidative stress inducer than other heavy metals. Of them, the expression of hsp20 and hsp70 genes was substantially modulated by exposure to heavy metals, indicating that these genes would provide a sensitive molecular biomarker for aquatic monitoring of heavy metal pollution. Copyright © 2014 Elsevier Inc. All rights reserved.

Epizoic and ectoparasitic protozoans from planktonic copepods of the southwest and southeast coasts of India with the description of a new species

Digital Repository Service at National Institute of Oceanography (India)

Santhakumari, V.

. pleuromammae are new records from the Indian Ocean. E. gemmipara as epizoic on copepods is recorded for the first time. A. sajirae is a new species belonging to the family Acinetidae. The epizoits and the ectoparasites were found infesting the appendages...

ACUTE TOXICITY OF FIVE SEDIMENT-ASSOCIATED METALS, INDIVIDUALLY AND IN A MIXTURE, TO THE ESTUARINE MEIOBENTHIC HARPACTICOID COPEPOD AMPHIASCUS TENUIREMIS. (R825279)

Science.gov (United States)

AbstractThe acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to me...

The response of three dominant Arctic copepod species to elevated CO2 concentrations and water temperatures

OpenAIRE

Hildebrandt, Nicole

2014-01-01

Ocean acidification (OA) and ocean warming are threatening marine life. Within the framework of the research project BIOACID, this thesis aims to provide a comprehensive overview on the sensitivity of the dominant Arctic calanoid copepod species Calanus finmarchicus, C. glacialis and C. hyperboreus to elevated pCO2 and temperatures. Controlled laboratory experiments have shown that subadult and adult Calanus life stages are rather robust to the direct effects of OA during both active and rest...

Population dynamic of high latitude copepods - with emphasis on Metridia longa

DEFF Research Database (Denmark)

Kjellerup, Sanne

2014-01-01

, sampling only the upper water column during the day-as is a usual procedure-would underestimate this potential key species. Reproduction patterns of the large calanoids suggested lifecycles adapted to the seasonal and episodic food availability, and consequently had a pulsed reproduction. In contrast...... in the fjord, was more restricted and indicated a life-history strategy that combines the advantages of eggcarrying with inter-clutch duration independent of hatching time. Our findings stress the need for sampling with small meshed nets, sampling deeper in the water column, and sampling both diurnally......High latitude ecosystems are shaped by seasonality in light, ranging from complete darkness in winter to midnight sun in summer, influencing both temperature and primary production. Copepods are important grazers on phytoplankton in marine systems and occupy a central role in the marine food...

Parasitic copepod (Lernaea cyprinacea) outbreaks in foothill yellow-legged frogs (Rana boylii) linked to unusually warm summers in northern California

Science.gov (United States)

Sarah J. Kupferberg; Alessandro Catenazzi; Kevin Lunde; Amy J. Lind; Wendy J. Palen

2009-01-01

How climate change may affect parasite–host assemblages and emerging infectious diseases is an important question in amphibian decline research. We present data supporting a link between periods of unusually warm summer water temperatures during 2006 and 2008 in a northern California river, outbreaks of the parasitic copepod Lernaea cyprinacea, and...

Effects of pyrene exposure and temperature on early development of two co-existing Arctic copepods

DEFF Research Database (Denmark)

Grenvald, Julie Cornelius; Nielsen, Torkel Gissel; Hjorth, Morten

2013-01-01

Oil exploration is expected to increase in the near future in Western Greenland. At present, effects of exposure to oil compounds on early life-stages of the ecologically important Calanus spp. are unknown. We investigated the effects of the oil compound pyrene, on egg hatching and naupliar...... with temperature at high pyrene concentration in C. finmarchicus. Both Calanus species were affected by pyrene exposure but C. finmarchicus was more sensitive compared to C. glacialis. Lowered growth rate and increased mortality of the naupliar stages entail reduced recruitment to copepod populations. Exposure...

The effects of mixed algal diets on population growth, egg productivity and nutritional profiles in cyclopoid copepods (Thermocyclops hyalinus and Mesocyclops aspericornis

Directory of Open Access Journals (Sweden)

Kumar Vidhya

2014-03-01

Full Text Available This experiment was carried out to evaluate the effect of mixed algal diet on dietary profiles of copepods. The microalgae like Spirulina platensis, Chlorella vulgaris and Azolla pinnata were mass cultured in artificial medium for a period of 20 days, cells are harvested, dried, powdered and used as feed. The small freshwater cyclopoids Thermocyclops hyalinus were compared to Mesocyclops aspericornis a species of copepod genera commonly preferred by most of the fish larvae. Both species are easily maintained in culture, when fed with mixed algal diets of equal ratios (1:1:1. Biochemical composition, egg production ratios, growth performance and fatty acids profile of the two different species were analyzed after an experimental period of 15 days, all the nutritional values were found to be high and statistically variable. On the basis of biochemical composition, egg production ratio, growth performance, amino acids and fatty acids profile it is found that M. aspericornis was the suitable candidate for larval fish diets.

Characterization of Stearoyl-CoA Desaturases from a Psychrophilic Antarctic Copepod, Tigriopus kingsejongensis.

Science.gov (United States)

Jung, Woongsic; Kim, Eun Jae; Han, Se Jong; Choi, Han-Gu; Kim, Sanghee

2016-10-01

Stearoyl-CoA desaturase is a key regulator in fatty acid metabolism that catalyzes the desaturation of stearic acid to oleic acid and controls the intracellular levels of monounsaturated fatty acids (MUFAs). Two stearoyl-CoA desaturases (SCD, Δ9 desaturases) genes were identified in an Antarctic copepod, Tigriopus kingsejongensis, that was collected in a tidal pool near the King Sejong Station, King George Island, Antarctica. Full-length complementary DNA (cDNA) sequences of two T. kingsejongensis SCDs (TkSCDs) were obtained from next-generation sequencing and isolated by reverse transcription PCR. DNA sequence lengths of the open reading frames of TkSCD-1 and TkSCD-2 were determined to be 1110 and 681 bp, respectively. The molecular weights deduced from the corresponding genes were estimated to be 43.1 kDa (TkSCD-1) and 26.1 kDa (TkSCD-2). The amino acid sequences were compared with those of fatty acid desaturases and sterol desaturases from various organisms and used to analyze the relationships among TkSCDs. As assessed by heterologous expression of recombinant proteins in Escherichia coli, the enzymatic functions of both stearoyl-CoA desaturases revealed that the amount of C16:1 and C18:1 fatty acids increased by greater than 3-fold after induction with isopropyl β-D-thiogalactopyranoside. In particular, C18:1 fatty acid production increased greater than 10-fold in E. coli expressing TkSCD-1 and TkSCD-2. The results of this study suggest that both SCD genes from an Antarctic marine copepod encode a functional desaturase that is capable of increasing the amounts of palmitoleic acid and oleic acid in a prokaryotic expression system.

A production season of turbot larvae Scophthalmus maximus (Linnaeus, 1758) reared on copepods in a Danish (56 degrees N) semi-intensive outdoor system

DEFF Research Database (Denmark)

Jepsen, Per M.; Jakobsen, Hans H.; Rayner, Thomas A.

2017-01-01

Turbot were reared from yolk sack larvae to juvenile in an outdoor semi-intensive system. Three production cycles were monitored from May to September. A pelagic food chain was established with phytoplankton, copepods and turbot larvae. Abiotic and biotic parameters of lower trophic levels together...

Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

NARCIS (Netherlands)

Plum, C.; Gollner, S.; Martinez Arbizu, P.; Bright, M.

2015-01-01

In order to characterize the copepod communitiesassociated with tubeworm and mussel aggregations around ahydrocarbon seep in the Green Canyon of the Gulf of Mexico,diversity, abundance, and community composition were analyzed.Also analyzed were species biogeography and the potentialconnectivity to

Magnetic light cloaking control in the marine planktonic copepod Sapphirina

Science.gov (United States)

Kashiwagi, H.; Mizukawa, Y.; Iwasaka, M.; Ohtsuka, S.

2017-05-01

We investigated the light cloaking behavior of the marine planktonic copepod Sapphirina under a magnetic field. Optical interferences in the multi-laminated guanine crystal layer beneath the dorsal body surface create a brilliant structural color, which can be almost entirely removed by changing the light reflection. In the investigation, we immersed segments of Sapphirina in seawater contained in an optical chamber. When the derived Sapphirina segments were attached to the container surface, they were inert to magnetic fields up to 300 mT. However, when the back plate segments were attached to the substrate at a point, with most of the plate floating in the seawater, the plate rotated oppositely to the applied magnetic field. In addition, the brilliant parts of the Sapphirina back plate rotated backward and forward by changing the magnetic field directions. Our experiment suggests a new model of an optical micro-electro-mechanical system that is controllable by magnetic fields.

Toxic effects of polyethylene terephthalate microparticles and Di(2-ethylhexyl)phthalate on the calanoid copepod, Parvocalanus crassirostris.

Science.gov (United States)

Heindler, Franz M; Alajmi, Fahad; Huerlimann, Roger; Zeng, Chaoshu; Newman, Stephen J; Vamvounis, George; van Herwerden, Lynne

2017-07-01

Large amounts of plastic end up in the oceans every year where they fragment into microplastics over time. During this process, microplastics and their associated plasticizers become available for ingestion by different organisms. This study assessed the effects of microplastics (Polyethylene terephthalate; PET) and one plasticizer (Di(2-ethylhexyl)phthalate; DEHP) on mortality, productivity, population sizes and gene expression of the calanoid copepod Parvocalanus crassirostris. Copepods were exposed to DEHP for 48h to assess toxicity. Adults were very healthy following chemical exposure (up to 5120µg L -1 ), whereas nauplii were severely affected at very low concentrations (48h LC 50 value of 1.04 ng L -1 ). Adults exposed to sub-lethal concentrations of DEHP (0.1-0.3µg L -1 ) or microplastics (10,000-80,000 particles mL -1 ) exhibited substantial reductions in egg production. Populations were exposed to either microplastics or DEHP for 6 days with 18 days of recovery or for 24 days. Populations exposed to microplastics for 24 days significantly depleted in population size (60±4.1%, pplastic and DEHP treatments after 6 days of exposure, but not after 18 days of recovery. Hsp70-like expression showed to be unresponsive to either DEHP or microplastic exposure. Clearly, microplastics and plasticizers pose a serious threat to zooplankton and potentially to higher trophic levels. Copyright © 2017 Elsevier Inc. All rights reserved.

Copepod distribution and biodiversity patterns from the surface to the deep sea along a latitudinal transect in the eastern Atlantic Ocean (24°N to 21°S)

Science.gov (United States)

Bode, Maya; Hagen, Wilhelm; Cornils, Astrid; Kaiser, Patricia; Auel, Holger

2018-02-01

Vertical distribution, community structure and diversity of calanoid copepods were studied at six stations along a latitudinal transect from 24°N to 21°S in the eastern Atlantic Ocean, resolving nine discrete depth layers to 2000 m. Total copepod abundances integrated from 0 to 2000 m ranged from 148,000 to 197,000 ind m-2. Usually, abundance and biomass were highest in the upper 100 m, exponentially decreasing with increasing depth. Only at the northern- and southernmost stations, a deeper biomass maximum was observed at 100-200 m and 200-400 m, respectively. In total, 26 families, 79 genera and at least 172 species were identified among calanoid copepods. Although there were certain regional differences in species composition between tropical and subtropical stations from north to south, depth had the strongest impact on the community structure of calanoids, resulting in statistically distinct communities in different depth zones. Maximum diversity of calanoids was observed between 100-200 m in the tropical zone and between 400-700 m in subtropical regions. Various interacting mechanisms such as vast spatial extent of the ecosystem, physical stability, avoidance from predators under dim light, small population sizes and high biologically generated heterogeneity possibly contribute to the biodiversity maxima in the twilight zone.

The efficiency of a new hydrodynamic cavitation pilot system on Artemia salina cysts and natural population of copepods and bacteria under controlled mesocosm conditions.

Science.gov (United States)

Cvetković, Martina; Grego, Mateja; Turk, Valentina

2016-04-15

A study of the efficiency of hydrodynamic cavitation and separation was carried out to evaluate an innovative, environmentally safe and acceptable system for ballast water treatment for reducing the risk of introducing non-native species worldwide. Mesocosm experiments were performed to assess the morphological changes and viability of zooplankton (copepods), Artemia salina cysts, and the growth potential of marine bacteria after the hydrodynamic cavitation treatment with a different number of cycles. Our preliminary results confirmed the significant efficiency of the treatment since more than 98% of the copepods and A. salina cysts were damaged, in comparison with the initial population. The efficiency increased with the number of the hydrodynamic cavitation cycles, or in combination with a separation technique for cysts. There was also a significant decrease in bacterial abundance and growth rate, compared to the initial number and growth potential. Copyright © 2015 Elsevier Ltd. All rights reserved.

Broad plasticity in the salinity tolerance of a marine copepod species, Acartia longiremis, in the Baltic Sea

DEFF Research Database (Denmark)

Dutz, Jörg; Christensen, Anette Maria

2018-01-01

, but decreased significantly at a lower salinity. Survival experiments showed a broad physiological plasticity with no increase in mortality upon immediate exposure to salinities of 16–7. Acclimation of females to low salinity extended the survival range to a salinity of 5. While the response in vital rates...... was characteristic of a tolerant, brackish water species, unusually high respiration rates at a salinity of 7–16 indicated that the species experienced osmotic stress, and that the mechanism maintaining physiological integrity was energetically expensive. Divergent responses of an increase in respiration rate...

Ecological dispersal barrier across the equatorial Atlantic in a migratory planktonic copepod

Science.gov (United States)

Goetze, Erica; Hüdepohl, Patricia T.; Chang, Chantel; Van Woudenberg, Lauren; Iacchei, Matthew; Peijnenburg, Katja T. C. A.

2017-11-01

Resolving the large-scale genetic structure of plankton populations is important to understanding their responses to climate change. However, few studies have reported on the presence and geographic extent of genetically distinct populations of marine zooplankton at ocean-basin scales. Using mitochondrial sequence data (mtCOI, 718 animals) from 18 sites across a basin-scale Atlantic transect (39°N-40°S), we show that populations of the dominant migratory copepod, Pleuromamma xiphias, are genetically subdivided across subtropical and tropical waters (global FST = 0.15, global ΦST = 0.21, both P marine plankton, and we suggest that this may be a dominant mechanism driving the large-scale genetic structure of zooplankton species. Our results also demonstrate the potential importance of the Atlantic equatorial province as a region of evolutionary novelty for the holoplankton.

Net-zooplankton abundance and biomass from Annaba Bay (SW Mediterranean Sea under estuarine influences

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M. OUNISSI

2016-07-01

Full Text Available Zooplankton samples were collected in Annaba Bay (Algeria from January 2009-March 2011 at three coastal sites differently affected by estuarine plumes and external currents. Aim of this survey was to analyze zooplankton composition, abundance and biomass and compare the results with previous studies to reveal possible populations and environmental changes. The mean zooplankton abundance varied between 1,200-6,000 ind. m-3 and biomass 6.70-25.70 mg DW m-3, according to the site. Copepods constituted the main fraction of zooplankton community, and Oithona similis and Paracalanus indicus successively dominated during autumn-winter and spring-summer. The dinoflagellate Noctiluca scintillans was one of the major zooplankton components, and developed high numbers during February-April, becoming common in neritic and coastal regions. The singularity of the zooplankton from Annaba Bay is the prevalence of P. indicus throughout the entire bay and the decrease in Acartia discaudata and A. clausi (with respect to previous years, possibly replaced by A. negligens. Additionally, Oithona nana abundance markedly decreased with the large development of O. similis. Annaba Bay also differs from other similar Mediterranean coastal areas by the large development of Centropages ponticus populations during the warm period. Among the identified copepod species, the alien species Pseudodiaptomus australiensis and P. arabicus are reported for the first time in the Mediterranean Sea. The occurrence of copepodid V stages of P. australiensis suggests that this species survives and reproduces in Annaba Bay, but so far without developing an abundant population.

Taxonomic resolutions based on 18S rRNA genes: a case study of subclass copepoda.

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Shu Wu

Full Text Available Biodiversity studies are commonly conducted using 18S rRNA genes. In this study, we compared the inter-species divergence of variable regions (V1-9 within the copepod 18S rRNA gene, and tested their taxonomic resolutions at different taxonomic levels. Our results indicate that the 18S rRNA gene is a good molecular marker for the study of copepod biodiversity, and our conclusions are as follows: 1 18S rRNA genes are highly conserved intra-species (intra-species similarities are close to 100%; and could aid in species-level analyses, but with some limitations; 2 nearly-whole-length sequences and some partial regions (around V2, V4, and V9 of the 18S rRNA gene can be used to discriminate between samples at both the family and order levels (with a success rate of about 80%; 3 compared with other regions, V9 has a higher resolution at the genus level (with an identification success rate of about 80%; and 4 V7 is most divergent in length, and would be a good candidate marker for the phylogenetic study of Acartia species. This study also evaluated the correlation between similarity thresholds and the accuracy of using nuclear 18S rRNA genes for the classification of organisms in the subclass Copepoda. We suggest that sample identification accuracy should be considered when a molecular sequence divergence threshold is used for taxonomic identification, and that the lowest similarity threshold should be determined based on a pre-designated level of acceptable accuracy.

Unsteady motion: escape jumps in planktonic copepods, their kinematics and energetics

DEFF Research Database (Denmark)

Kiørboe, Thomas; Andersen, Anders Peter; Langlois, Vincent J.

2010-01-01

velocities in other aquatic organisms. The relative duration of the pauses between power strokes was observed to increase with organism size. We demonstrate that this is an inherent property of swimming by alternating power strokes and pauses. We finally show that the Strouhal number is in the range of peak......We describe the kinematics of escape jumps in three species of 0.3–3.0 mm-sized planktonic copepods. We find similar kinematics between species with periodically alternating power strokes and passive coasting and a resulting highly fluctuating escape velocity. By direct numerical simulations, we...... estimate the force and power output needed to accelerate and overcome drag. Both are very high compared with those of other organisms, as are the escape velocities in comparison to startle velocities of other aquatic animals. Thus, the maximum weight-specific force, which for muscle motors of other animals...

Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS

Energy Technology Data Exchange (ETDEWEB)

Han, Jeonghoon; Won, Eun-Ji; Lee, Min-Chul [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Seo, Jung Soo [Pathology Team, National Fisheries Research & Development Institute, Busan 619-902 (Korea, Republic of); Lee, Su-Jae [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2015-08-15

Highlights: • The repercussions of BDE-47 and PFOS were occurred on development and fecundity. • BDE-47 and PFOS can induce oxidative stress through the generation of ROS. • The expression of defensome was changed in response to BDE-47 and PFOS. • ROS-induced DNA damage in BDE-47 and PFOS exposure lead to apoptosis and DNA repair. - Abstract: 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and perfluorooctane sulfonate (PFOS) are widely dispersed persistent organic pollutants (POPs) in the marine ecosystem. However, their toxic effects on marine organisms are still poorly understood. In this study, we investigated the effects of BDE-47 and PFOS on development and reproduction at the organismal level and reactive oxygen species (ROS) production and gene expression patterns of the defensome at the cellular level in the intertidal copepod Tigriopus japonicus. In copepods exposed to BDE-47 and PFOS, we observed developmental retardation and reduced fecundity, suggesting repercussions on in vivo endpoints through alterations to the normal molting and reproduction system of T. japonicus. BDE-47 and PFOS increased levels of ROS in T. japonicus in a concentration-dependent manner, indicating that POPs can induce oxidative stress through the generation of ROS. Additionally, transcript profiles of genes related to detoxification (e.g., CYPs), antioxidant functions (e.g., GST- sigma, catalase, MnSOD), apoptosis (e.g., p53, Rb), and cellular proliferation (e.g., PCNA) were modulated over 72 h in response to BDE-47 (120 μg/L) and PFOS (1000 μg/L). These findings indicate that BDE-47 and PFOS can induce oxidative stress-mediated DNA damage repair systems with transcriptional regulation of detoxification, antioxidant, and apoptosis-related genes, resulting in developmental retardation and reduced fecundity in the copepod T. japonicus.

Developmental retardation, reduced fecundity, and modulated expression of the defensome in the intertidal copepod Tigriopus japonicus exposed to BDE-47 and PFOS

International Nuclear Information System (INIS)

Han, Jeonghoon; Won, Eun-Ji; Lee, Min-Chul; Seo, Jung Soo; Lee, Su-Jae; Lee, Jae-Seong

2015-01-01

Highlights: • The repercussions of BDE-47 and PFOS were occurred on development and fecundity. • BDE-47 and PFOS can induce oxidative stress through the generation of ROS. • The expression of defensome was changed in response to BDE-47 and PFOS. • ROS-induced DNA damage in BDE-47 and PFOS exposure lead to apoptosis and DNA repair. - Abstract: 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and perfluorooctane sulfonate (PFOS) are widely dispersed persistent organic pollutants (POPs) in the marine ecosystem. However, their toxic effects on marine organisms are still poorly understood. In this study, we investigated the effects of BDE-47 and PFOS on development and reproduction at the organismal level and reactive oxygen species (ROS) production and gene expression patterns of the defensome at the cellular level in the intertidal copepod Tigriopus japonicus. In copepods exposed to BDE-47 and PFOS, we observed developmental retardation and reduced fecundity, suggesting repercussions on in vivo endpoints through alterations to the normal molting and reproduction system of T. japonicus. BDE-47 and PFOS increased levels of ROS in T. japonicus in a concentration-dependent manner, indicating that POPs can induce oxidative stress through the generation of ROS. Additionally, transcript profiles of genes related to detoxification (e.g., CYPs), antioxidant functions (e.g., GST- sigma, catalase, MnSOD), apoptosis (e.g., p53, Rb), and cellular proliferation (e.g., PCNA) were modulated over 72 h in response to BDE-47 (120 μg/L) and PFOS (1000 μg/L). These findings indicate that BDE-47 and PFOS can induce oxidative stress-mediated DNA damage repair systems with transcriptional regulation of detoxification, antioxidant, and apoptosis-related genes, resulting in developmental retardation and reduced fecundity in the copepod T. japonicus

A deep transcriptomic resource for the copepod crustacean Labidocera madurae: A potential indicator species for assessing near shore ecosystem health.

Directory of Open Access Journals (Sweden)

Vittoria Roncalli

Full Text Available Coral reef ecosystems of many sub-tropical and tropical marine coastal environments have suffered significant degradation from anthropogenic sources. Research to inform management strategies that mitigate stressors and promote a healthy ecosystem has focused on the ecology and physiology of coral reefs and associated organisms. Few studies focus on the surrounding pelagic communities, which are equally important to ecosystem function. Zooplankton, often dominated by small crustaceans such as copepods, is an important food source for invertebrates and fishes, especially larval fishes. The reef-associated zooplankton includes a sub-neustonic copepod family that could serve as an indicator species for the community. Here, we describe the generation of a de novo transcriptome for one such copepod, Labidocera madurae, a pontellid from an intensively-studied coral reef ecosystem, Kāne'ohe Bay, Oahu, Hawai'i. The transcriptome was assembled using high-throughput sequence data obtained from whole organisms. It comprised 211,002 unique transcripts, including 72,391 with coding regions. It was assessed for quality and completeness using multiple workflows. Bench-marking-universal-single-copy-orthologs (BUSCO analysis identified transcripts for 88% of expected eukaryotic core proteins. Targeted gene-discovery analyses included searches for transcripts coding full-length "giant" proteins (>4,000 amino acids, proteins and splice variants of voltage-gated sodium channels, and proteins involved in the circadian signaling pathway. Four different reference transcriptomes were generated and compared for the detection of differential gene expression between copepodites and adult females; 6,229 genes were consistently identified as differentially expressed between the two regardless of reference. Automated bioinformatics analyses and targeted manual gene curation suggest that the de novo assembled L. madurae transcriptome is of high quality and completeness. This

A deep transcriptomic resource for the copepod crustacean Labidocera madurae: A potential indicator species for assessing near shore ecosystem health

Science.gov (United States)

Christie, Andrew E.; Sommer, Stephanie A.; Cieslak, Matthew C.; Hartline, Daniel K.; Lenz, Petra H.

2017-01-01

Coral reef ecosystems of many sub-tropical and tropical marine coastal environments have suffered significant degradation from anthropogenic sources. Research to inform management strategies that mitigate stressors and promote a healthy ecosystem has focused on the ecology and physiology of coral reefs and associated organisms. Few studies focus on the surrounding pelagic communities, which are equally important to ecosystem function. Zooplankton, often dominated by small crustaceans such as copepods, is an important food source for invertebrates and fishes, especially larval fishes. The reef-associated zooplankton includes a sub-neustonic copepod family that could serve as an indicator species for the community. Here, we describe the generation of a de novo transcriptome for one such copepod, Labidocera madurae, a pontellid from an intensively-studied coral reef ecosystem, Kāne‘ohe Bay, Oahu, Hawai‘i. The transcriptome was assembled using high-throughput sequence data obtained from whole organisms. It comprised 211,002 unique transcripts, including 72,391 with coding regions. It was assessed for quality and completeness using multiple workflows. Bench-marking-universal-single-copy-orthologs (BUSCO) analysis identified transcripts for 88% of expected eukaryotic core proteins. Targeted gene-discovery analyses included searches for transcripts coding full-length “giant” proteins (>4,000 amino acids), proteins and splice variants of voltage-gated sodium channels, and proteins involved in the circadian signaling pathway. Four different reference transcriptomes were generated and compared for the detection of differential gene expression between copepodites and adult females; 6,229 genes were consistently identified as differentially expressed between the two regardless of reference. Automated bioinformatics analyses and targeted manual gene curation suggest that the de novo assembled L. madurae transcriptome is of high quality and completeness. This

Transgenerational effects alleviate severe fecundity loss during ocean acidification in a ubiquitous planktonic copepod.

Science.gov (United States)

Thor, Peter; Dupont, Sam

2015-06-01

Ocean acidification (OA) caused by anthropogenic CO2 emission is projected for thousands of years to come, and significant effects are predicted for many marine organisms. While significant evolutionary responses are expected during such persistent environmental change, most studies consider only short-term effects. Little is known about the transgenerational effects of parental environments or natural selection on the capacity of populations to counter detrimental OA effects. In this study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 μatm) and grown for two generations at these conditions. Our results show evidence of alleviation of OA effects as a result of transgenerational effects in P. acuspes. Second generation adults showed a 29% decrease in fecundity at 900 μatm CO2 compared to 400 μatm CO2 . This was accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 μatm), fecundity would have decreased by as much as 67% compared to at 400 μatm CO2 as a result of this plasticity. However, transgenerational effects partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900 μatm CO2 . This also relieved the copepods from metabolic stress, and respiration rates were lower than at 900 μatm CO2 . These results highlight the importance of tests for transgenerational effects to avoid overestimation of the effects of OA. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Life-history responses to changing temperature and salinity of the Baltic Sea copepod Eurytemora affinis.

Science.gov (United States)

Karlsson, Konrad; Puiac, Simona; Winder, Monika

2018-01-01

To understand the effects of predicted warming and changing salinity of marine ecosystems, it is important to have a good knowledge of species vulnerability and their capacity to adapt to environmental changes. In spring and autumn of 2014, we conducted common garden experiments to investigate how different populations of the copepod Eurytemora affinis from the Baltic Sea respond to varying temperatures and salinity conditions. Copepods were collected in the Stockholm archipelago, Bothnian Bay, and Gulf of Riga (latitude, longitude: 58°48.19', 17°37.52'; 65°10.14', 23°14.41'; 58°21.67', 24°30.83'). Using individuals with known family structure, we investigated within population variation of the reaction norm (genotype and salinity interaction) as a means to measure adaptive capacity. Our main finding was that low salinity has a detrimental effect on development time, the additive effects of high temperature and low salinity have a negative effect on survival, and their interaction has a negative effect on hatching success. We observed no variation in survival and development within populations, and all genotypes had similar reaction norms with higher survival and faster development in higher salinities. This suggests that there is no single genotype that performs better in low salinity or high salinity; instead, the best genotype in any given salinity is best in all salinities. Genotypes with fast development time also had higher survival compared to slow developing genotypes at all salinities. Our results suggest that E. affinis can tolerate close to freshwater conditions also in high temperatures, but with a significant reduction in fitness.

Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia

Science.gov (United States)

Huang, Ying; Zhu, Liyan; Qiu, Xuchun; Zhang, Tianwen

2010-03-01

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L-1 were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L-1. The percentages of ovigerous females were reduced compared with the control ( P<0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L-1. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase ( r m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng L-1), where all females aborted their egg sacs, 20 ng TBTO L-1 was the only concentration that significantly decreased r m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.

Algal grazing by the planktonic copepods Centropages hamatus and Pseudocalanus sp.: Diurnal and seasonal variation during the spring phytoplankton bloom in the Øresund Denmark

DEFF Research Database (Denmark)

Nicolajsen, Hanne; Møhlenberg, Flemming; Kiørboe, Thomas

1983-01-01

Seasonal and diel variation in rate of algal grazing were estimated from measurements of gut content (plant pigments) and gut turnover in the copepods C. hamatus and Pseudocalanus sp. during spring (Jan.-May) in the Oresund. Both species exhibited significant diel variation in gut content...

BDE-47 causes developmental retardation with down-regulated expression profiles of ecdysteroid signaling pathway-involved nuclear receptor (NR) genes in the copepod Tigriopus japonicus.

Science.gov (United States)

Hwang, Dae-Sik; Han, Jeonghoon; Won, Eun-Ji; Kim, Duck-Hyun; Jeong, Chang-Bum; Hwang, Un-Ki; Zhou, Bingsheng; Choe, Joonho; Lee, Jae-Seong

2016-08-01

2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) is a persistent organic pollutant (POP) in marine environments. Despite its adverse effects (e.g. developmental retardation) in ecdysozoa, the effects of BDE-47 on transcription of ecdysteroid signaling pathway-involved-nuclear receptor (NR) genes and metamorphosis-related genes have not been examined in copepods. To examine the deleterious effect of BDE-47 on copepod molting and metamorphosis, BDE-47 was exposed to the harpacticoid copepod Tigriopus japonicus, followed by monitoring developmental retardation and transcriptional alteration of NR genes. The developmental rate was significantly inhibited (P<0.05) in response to BDE-47 and the agricultural insecticide gamma-hexachlorocyclohexane. Conversely, the ecdysteroid agonist ponasterone A (PoA) led to decreased molting and metamorphosis time (P<0.05) from the nauplius stage to the adult stage. In particular, expression profiles of all NR genes were the highest at naupliar stages 5-6 except for SVP, FTZ-F1, and HR96 genes. Nuclear receptor USP, HR96, and FTZ-F1 genes also showed significant sex differences (P<0.05) in gene expression levels over different developmental stages, indicating that these genes may be involved in vitellogenesis. NR gene expression patterns showed significant decreases (P<0.05) in response to BDE-47 exposure, implying that molting and metamorphosis retardation is likely associated with NR gene expression. In summary, BDE-47 leads to molting and metamorphosis retardation and suppresses transcription of NR genes. This information will be helpful in understanding the molting and metamorphosis delay mechanism in response to BDE-47 exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensitivity of adult and embryonic calanoid copepods to acute ionizing radiation

International Nuclear Information System (INIS)

Gehrs, C.W.; Trabalka, J.R.; Bardill, E.A.

1975-01-01

Effects of 60 Co γ-rays on adult and embryonic calanoid copepods (Diaptomus clavipes Schact) were determined following acute doses of 0, 1, 10, and 100 krads. Mean survivorship of adults ranged from 3.1 to 45.2 days (100 krad and controls, respectively) and decreased significantly at each increase in dose. The 100-krad dose effected 100 percent mortality to all embryos. Whereas all clutches in the controls had some hatching success, a progressive increase in percentage of clutches in which no hatching took place was seen over the dose range used. Nearly twice as many clutches were dropped in the irradiated group as in the controls. While a significant decrease in hatching success with increasing dose was observed when all clutches were compared, this was not the case at the lowest dose for carried clutches. Possibly the females are able to assess the physiological state of the embryos carried and eject clutches containing damaged eggs. (U.S.)

A gene-based SNP resource and linkage map for the copepod Tigriopus californicus

Directory of Open Access Journals (Sweden)

Foley Brad R

2011-11-01

Full Text Available Abstract Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct a linkage map dense enough for quantitative trait locus detection in an interval mapping framework for T. californicus--a first for copepods. Results One hundred and ninety Single Nucleotide Polymorphisms (SNPs were used to genotype our mapping population of 250 F2 larvae. We were able to construct a linkage map with an average intermarker distance of 1.8 cM, and a maximum intermarker distance of 10.3 cM. All markers were assembled into linkage groups, and the 12 linkage groups corresponded to the 12 known chromosomes of T. californicus. We estimate a total genome size of 401.0 cM, and a total coverage of 73.7%. Seventy five percent of the mapped markers were detected in 9 additional populations of T. californicus. Of available model arthropod genomes, we were able to show more colocalized pairs of homologues between T. californicus and the honeybee Apis mellifera, than expected by chance, suggesting preserved macrosynteny between Hymenoptera and Copepoda. Conclusions Our study provides an abundance of linked markers spanning all chromosomes. Many of these markers are also found in multiple populations of T. californicus, and in two other species in the genus. The genomic resource we have developed will enable mapping throughout the geographical range of this species and in closely related species. This linkage map will facilitate genome sequencing, mapping and assembly in an ecologically and taxonomically interesting group for which genomic resources are

A gene-based SNP resource and linkage map for the copepod Tigriopus californicus

Science.gov (United States)

2011-01-01

Background As yet, few genomic resources have been developed in crustaceans. This lack is particularly evident in Copepoda, given the extraordinary numerical abundance, and taxonomic and ecological diversity of this group. Tigriopus californicus is ideally suited to serve as a genetic model copepod and has been the subject of extensive work in environmental stress and reproductive isolation. Accordingly, we set out to develop a broadly-useful panel of genetic markers and to construct a linkage map dense enough for quantitative trait locus detection in an interval mapping framework for T. californicus--a first for copepods. Results One hundred and ninety Single Nucleotide Polymorphisms (SNPs) were used to genotype our mapping population of 250 F2 larvae. We were able to construct a linkage map with an average intermarker distance of 1.8 cM, and a maximum intermarker distance of 10.3 cM. All markers were assembled into linkage groups, and the 12 linkage groups corresponded to the 12 known chromosomes of T. californicus. We estimate a total genome size of 401.0 cM, and a total coverage of 73.7%. Seventy five percent of the mapped markers were detected in 9 additional populations of T. californicus. Of available model arthropod genomes, we were able to show more colocalized pairs of homologues between T. californicus and the honeybee Apis mellifera, than expected by chance, suggesting preserved macrosynteny between Hymenoptera and Copepoda. Conclusions Our study provides an abundance of linked markers spanning all chromosomes. Many of these markers are also found in multiple populations of T. californicus, and in two other species in the genus. The genomic resource we have developed will enable mapping throughout the geographical range of this species and in closely related species. This linkage map will facilitate genome sequencing, mapping and assembly in an ecologically and taxonomically interesting group for which genomic resources are currently under development

The impact of a power plant discharge on the distribution of Harpacticoid copepods on a sandy shore at Kalpakkam, east coast of India

International Nuclear Information System (INIS)

Suresh, K.; Ahamed, M.S.; Durairaj, G.; Nair, K.V.K.

1994-01-01

Thermal liquid discharges to a water body changes the biological environment existing in and around the water sources. This paper describes studies on the distribution of Harpacticoid copepods around Madras Atomic Power Station. The temperature of the water dictated the spatial and temporal distribution of the species occurring in this area. (author). 15 refs., 4 figs

Gene expression analyses of immune responses in Atlantic salmon during early stages of infection by salmon louse (Lepeophtheirus salmonis revealed bi-phasic responses coinciding with the copepod-chalimus transition

Directory of Open Access Journals (Sweden)

Afanasyev Sergey

2011-03-01

Full Text Available Abstract Background The salmon louse (Lepeophtheirus salmonis Krøyer, an ectoparasitic copepod with a complex life cycle causes significant losses in salmon aquaculture. Pesticide treatments against the parasite raise environmental concerns and their efficacy is gradually decreasing. Improvement of fish resistance to lice, through biological control methods, needs better understanding of the protective mechanisms. We used a 21 k oligonucleotide microarray and RT-qPCR to examine the time-course of immune gene expression changes in salmon skin, spleen, and head kidney during the first 15 days after challenge, which encompassed the copepod and chalimus stages of lice development. Results Large scale and highly complex transcriptome responses were found already one day after infection (dpi. Many genes showed bi-phasic expression profiles with abrupt changes between 5 and 10 dpi (the copepod-chalimus transitions; the greatest fluctuations (up- and down-regulation were seen in a large group of secretory splenic proteases with unknown roles. Rapid sensing was witnessed with induction of genes involved in innate immunity including lectins and enzymes of eicosanoid metabolism in skin and acute phase proteins in spleen. Transient (1-5 dpi increase of T-cell receptor alpha, CD4-1, and possible regulators of lymphocyte differentiation suggested recruitment of T-cells of unidentified lineage to the skin. After 5 dpi the magnitude of transcriptomic responses decreased markedly in skin. Up-regulation of matrix metalloproteinases in all studied organs suggested establishment of a chronic inflammatory status. Up-regulation of putative lymphocyte G0/G1 switch proteins in spleen at 5 dpi, immunoglobulins at 15 dpi; and increase of IgM and IgT transcripts in skin indicated an onset of adaptive humoral immune responses, whereas MHCI appeared to be down-regulated. Conclusions Atlantic salmon develops rapid local and systemic reactions to L. salmonis, which, however

De novo transcriptome assembly of the calanoid copepod Neocalanus flemingeri: A new resource for emergence from diapause.

Science.gov (United States)

Roncalli, Vittoria; Cieslak, Matthew C; Sommer, Stephanie A; Hopcroft, Russell R; Lenz, Petra H

2018-02-01

Copepods, small planktonic crustaceans, are key links between primary producers and upper trophic levels, including many economically important fishes. In the subarctic North Pacific, the life cycle of copepods like Neocalanus flemingeri includes an ontogenetic migration to depth followed by a period of diapause (a type of dormancy) characterized by arrested development and low metabolic activity. The end of diapause is marked by the production of the first brood of eggs. Recent temperature anomalies in the North Pacific have raised concerns about potential negative effects on N. flemingeri. Since diapause is a developmental program, its progress can be tracked using through global gene expression. Thus, a reference transcriptome was developed as a first step towards physiological profiling of diapausing females using high-throughput Illumina sequencing. The de novo transcriptome, the first for this species was designed to investigate the diapause period. RNA-Seq reads were obtained for dormant to reproductive N. flemingeri females. A high quality de novo transcriptome was obtained by first assembling reads from each individual using Trinity software followed by clustering with CAP3 Assembly Program. This assembly consisted of 140,841transcripts (contigs). Bench-marking universal single-copy orthologs analysis identified 85% of core eukaryotic genes, with 79% predicted to be complete. Comparison with other calanoid transcriptomes confirmed its quality and degree of completeness. Trinity assembly of reads originating from multiple individuals led to fragmentation. Thus, the workflow applied here differed from the one recommended by Trinity, but was required to obtain a good assembly. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.